Strapping Seals & Buckles: Strapping Fasteners for Steel and Plastic
JUHONG makes strapping seals for steel, polyester and PP strapping in Changzhou, China, and supplies wire buckles for PP and cord strapping. Our plant turns out about 300 million metal seals a year, from 1/2 in to 2 in wide, for manual tools, pneumatic tools and automatic strapping machines. JUHONG is one of the drafting organizations of GB/T 39040-2020, China’s national standard for steel seals and edge protectors for packing.
Trusted by Global Industrial Buyers
They are the fasteners that hold the two ends of a tensioned band together. A seal is a short steel sleeve placed over both ends. A hand or pneumatic tool presses the sleeve, or cuts notches through sleeve and band, and the joint locks. A buckle is a formed steel wire loop: the band is threaded through by hand and pulled tight, and friction holds it with no tool needed.
Seals work on all types of strapping material: steel, polyester (PET) and polypropylene (PP). The wire type is used on light-duty polypropylene strapping, woven and composite cord strapping, and cut-length PET baling strap. On purchase orders they often appear as strapping clips or banding clips.
Steel seals a year from our Changzhou plant
Push, snap-on, thread-on, open-flange, serrated, magazine, cross and right-angle
Seal widths for 12.7 to 50 mm strapping
Seal thickness, cold rolled or zinc coated
Which Joint Do You Need?
| Seal: strapping | Steel, polyester, PP |
|---|---|
| Seal: tool | Manual or pneumatic sealer, combination tool, or an automatic machine |
| Seal: joint | Notch or crimp joint as in ASTM D3953: one seal with 2 pairs of notches, or 3 to 4 pairs of crimps; permanent once sealed |
| Seal: typical loads | Steel coils, pipes, bricks, timber, heavy loads |
| Buckle: strapping | PP, cord / composite, PET baling strap |
| Buckle: tool | Hand threading; a tensioner for tight loads |
| Buckle: joint | Threaded loop, can be re-tightened |
| Buckle: typical loads | Cartons, cotton bales, containers secured with cord strapping |
Types of Strapping Seals We Make
Six main types and two special shapes. Choose by your strapping and your tool. Every type has its sizes and a dimension drawing in the size tables below.
Also called pusher seals or closed seals. Both flanges fold in and overlap. It is slid onto the band before tightening and closed with a push-type tool.
Also called open seals. Flanges are formed to less than 90°. Placed over the band after tightening, pressed partly shut by hand, then locked by the tool.
Both flanges fold in but stop short of each other. Threaded onto the band before it goes around the load.
A thread-on shape with one flange turned outward to guide the band. For 1 and 1-1/4 in steel strapping.
An open type with teeth inside that bite into plastic strapping. Made in dotted and diagonal-tooth styles.
Flanges open outward so the seals nest into a stack for the magazine of an automatic steel strapping machine.
Cross-Shaped and Right-Angle Seals
Two special seals for straps that cross or meet at an angle. Demand is lower than for the six main types, so tell us the strap size and the quantity you need.
Cross-shaped seal
Joins two steel straps where they cross each other. 148 mm long, for 1-1/4 in strapping.
Right-angle seal
Two seals joined at 90°, for straps that meet at a right angle. 1-1/4 in, 0.7 mm thick.
Strapping Seal Applications by Industry
Our seals and buckles close steel, PET, PP and cord strapping on these loads. Tell us the load and we will suggest the strap and the matching seal.
Push and magazine seals on high tensile steel strapping, through the eye and around the coil.
Seals lock the bands that hold each coil together for lifting and shipping.
Steel strapping and seals on non-ferrous coils.
Push and thread-on seals on 3/4 to 1-1/4 in steel strapping.
Magazine seals feed the sealing head of automatic steel strapping machines.
Seals matched to the jaws of the sealing head on your machine or tool.
Serrated seals on PET and PP strapping.
Timber and plywood, bricks and blocks, glass and stone, paper rolls and board go out on the same steel and PET strapping and seals. Cotton bales use wire buckles. Tell us your load →
Seal Sizes & Specifications
Standard sizes from our catalog. Pick a seal type to see every width, length and thickness we make, with a drawing that shows where each dimension is measured. Carton counts are in the spec sheet on our Downloads page.
Push Type Sizes
Both flanges fold in and meet on top. Slid onto the band before tightening and closed with a push-type tool.
Drawing after GB/T 39040-2020: L length along the band, W outside width, H height, T steel thickness, B overlap of the flanges, R bend radius.
| Width | Length × thickness |
|---|---|
| 1/2 in (12.7 mm) | 22 mm × 0.6 mm (0.86 × .023 in) |
| 5/8 in (16 mm) | 22 / 25 mm × 0.6 mm (0.86 / 0.98 × .023 in) |
| 3/4 in (19 mm) | 22 / 25 / 32 / 40 mm × 0.6 mm (0.86 / 0.98 / 1.26 / 1.57 × .023 in) 40 / 45 mm × 0.7 mm (1.57 / 1.77 × .028 in) 45 / 48 mm × 0.8 mm (1.77 / 1.89 × .031 in) 45 / 48 / 50 / 55 / 57 mm × 0.9 mm (1.77 / 1.89 / 2 / 2.16 / 2.24 × .035 in) |
| 1 in (25 mm) | 48 mm × 0.8 mm (1.89 × .031 in) 48 / 50 mm × 0.9 mm (1.89 / 2 × .035 in) |
| 1-1/4 in (32 mm) | 40 / 45 / 48 / 55 mm × 0.7 mm (1.57 / 1.77 / 1.89 / 2.16 × .028 in) 45 / 48 mm × 0.8 mm (1.77 / 1.89 × .031 in) 38 / 45 / 48 / 50 / 53 / 55 / 57 / 75 mm × 0.9 mm (1.5 / 1.77 / 1.89 / 2 / 2.08 / 2.16 / 2.24 / 2.95 × .035 in) |
Snap-on Type Sizes
An open type placed over the band after tightening, so nothing has to be threaded.
Drawing after GB/T 39040-2020: L length along the band, W outside width, D opening width, M arm width, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 1/2 in (12.7 mm) | 32 mm × 0.6 mm (1.26 × .023 in) |
| 5/8 in (16 mm) | 32 mm × 0.6 mm (1.26 × .023 in) |
| 3/4 in (19 mm) | 32 mm × 0.6 mm (1.26 × .023 in) |
Thread-on Type Sizes
Semi-open: both flanges fold in but stop short of each other. Threaded onto the band before it goes around the load.
Drawing after GB/T 39040-2020: L length along the band, W outside width, H height, D opening width, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 3/4 in (19 mm) | 55 mm × 0.9 mm (2.16 × .035 in) |
| 1-1/4 in (32 mm) | 40 / 45 mm × 0.7 mm (1.57 / 1.77 × .028 in) 45 mm × 0.8 mm (1.77 × .031 in) 48 / 50 mm × 0.9 mm (1.89 / 2 × .035 in) |
Open-flange Type Sizes
Semi-closed, with one flange turned outward, for wider steel strapping.
Drawing after GB/T 39040-2020: L length along the band, W outside width, H height, M arm width, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 1 in (25 mm) | 55 mm × 0.9 mm (2.16 × .035 in) |
| 1-1/4 in (32 mm) | 55 mm × 0.9 mm (2.16 × .035 in) |
Serrated Type Sizes
An open type with teeth inside that bite into polyester and polypropylene strapping, in dotted and diagonal-tooth styles. It is measured like the snap-on type.
Measured as in GB/T 39040-2020: L length along the band, W outside width, D opening width, M arm width, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 1/2 in (12.7 mm) | 28 mm × 0.6 mm (1.10 × .023 in) 26 mm × 0.7 mm (1.02 × .028 in) |
| 5/8 in (16 mm) | 28 mm × 0.6 mm (1.10 × .023 in) 26 mm × 0.7 mm (1.02 × .028 in) |
| 3/4 in (19 mm) | 28 mm × 0.6 mm (1.10 × .023 in) 26 mm × 0.7 mm (1.02 × .028 in) |
Magazine Type Sizes
Outward flanges let them nest into a stack for the magazine of an automatic steel strapping machine. Machine fit, packing and free samples are on our magazine seals page.
Drawing after GB/T 39040-2020: L length along the band, W outside width, H height, D opening width, T steel thickness.
| Width | Length × thickness |
|---|---|
| 3/4 in (19 mm) | 28 mm × 0.6 mm (1.10 × .023 in) |
| 1-1/4 in (32 mm) | 38 mm × 0.8 mm (1.5 × .031 in) 38 / 40 / 50 mm × 1 mm (1.5 / 1.57 / 2 × .040 in) 51 mm × 1.1 mm (2 × .043 in) |
| 2 in (50 mm) | 75 mm × 1 mm (2.95 × .040 in) 75 mm × 1.2 mm (2.95 × .05 in) |
Cross-shaped Type Sizes
Joins two steel straps where they cross each other.
Drawing after GB/T 39040-2020: L length along the band, W outside width, D opening width, M arm width, H height, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 1-1/4 in (32 mm) | 148 mm × 0.9 mm (5.8 × .035 in) |
Right-angle Type Sizes
Two seals joined at 90°, for straps that meet at a right angle.
Drawing after GB/T 39040-2020: W outside width, E horizontal width, M arm width, H height, T steel thickness, R bend radius.
| Width | Length × thickness |
|---|---|
| 1-1/4 in (32 mm) | 0.7 mm thick (.028 in) |
How to Choose a Strapping Seal
Choose a seal in four steps: the strap it closes, the strap size, the tool that closes it and where the load goes.
Match the seal to the strap
Steel strap takes push, snap-on, thread-on, open-flange or magazine seals. PET and PP strap take serrated seals. PP and cord strap can also be closed with wire buckles.
Same width as the strap
Use a seal of the same width as your strapping. High tensile steel needs a longer, thicker sleeve.
Pick open, closed or magazine
Pick open or closed types to suit your hand or pneumatic tool, and magazine seals for automatic lines. If you are not sure, send us a photo of the tool jaws.
Choose the finish
Cold rolled seals suit indoor storage and normal shipping. Zinc-coated seals resist rust and corrosion in damp warehouses, outdoor storage and sea freight.
Most-Ordered Strapping Seal Sizes
A size is written as length × width × thickness, where the width is the strap width the seal fits. Carton counts are our standard packing from the spec sheet; we can pack other counts on request.
| Size (L × W × T) | Type | Standard pieces per carton |
|---|---|---|
| 32 × 16 × 0.6 mm | Snap-on (open) | 2,000 |
| 32 × 19 × 0.6 mm | Snap-on (open) | 2,000 |
| 45 × 19 × 0.8 mm | Push (closed) | 1,000 |
| 48 × 19 × 0.8 mm | Push (closed) | 1,000 |
| 48 × 32 × 0.8 mm | Push (closed) | 1,000 |
| 48 × 32 × 0.9 mm | Push (closed) | 1,000 |
| 50 × 32 × 0.9 mm | Push (closed) | 1,000 |
| 55 × 32 × 0.9 mm | Push (closed) | 1,000 |
| 57 × 32 × 0.9 mm | Push (closed) | Ask us |
| 50 × 32 × 1.0 mm | Magazine | 500 or 1,000 |
Seal Codes in ASTM D3953 and GB/T 39040-2020
ASTM D3953, the US specification for flat steel strapping and seals, groups seals by style (I to V) and by class: R for regular duty and H for heavy duty. China’s GB/T 39040-2020 uses a type letter and writes a seal as letter, thickness × strap width × length: P0.9×32×50 is the push type, 0.9 mm thick, for 32 mm strapping, 50 mm long. It allows ±0.035 mm on thickness and ±0.5 mm on the length and width of manual seals. The outside width W is a little larger than the strap: the push type for 32 mm strapping measures about 35.5 mm across.
| Seal type | ASTM D3953 style | GB/T 39040 letter | Typical use |
|---|---|---|---|
| Snap-on (open) | I | S | Steel strap, placed after tightening |
| Thread-on (semi-open) | II | T | Steel strap, threaded before strapping |
| Push (closed) | III | P | Steel strap, push-type tools |
| Magazine | IV | M | Automatic steel strapping machines |
| Cross-shaped | V | CA / CB | Straps that cross each other |
| Open-flange (semi-closed) | — | F | Wider steel strap |
| Right-angle | — | R | Straps that meet at 90° |
Strapping Buckles for Light Duty PP and Cord Strapping
Also called wire or banding buckles, these steel wire loops close PP and woven or composite cord strapping. They are the usual choice when there is no sealing tool on site, or when a band may need re-tightening after the load settles. Cotton gins use them on cut-length PET baling strap too.
We supply metal strapping buckles for poly and cord strapping alongside our seals, so one order covers both joint types. Tell us your strapping type and width, and we will quote the matching buckle.
Wire Buckles for PP and Cord Strapping
A formed steel wire loop. The band is threaded through it and tightened, and it holds without any tool.
Send your strapping type and width. We supply the buckle that matches it, in the same shipment as your seals and strap.
How to Use Strapping Buckles and Seals
Wear gloves and eye protection when securing loads. A tensioned band can spring back when cut.
Buckle 1 · Thread and lock
Thread one end of the band through the loop and fold it back so it locks.
Buckle 2 · Wrap and tighten
Pass the strapping around the bundle, thread the free end through from the other side, pull it tight and cut off the spare length.
Seal 1 · Overlap and tension
Put the strapping around the load with one end lying over the other, then tighten it with a tensioner.
Seal 2 · Close and cut
Place the sleeve over both ends, close it with the sealer, then cut the band from the coil.
Strapping Seals for Steel and PET Strapping
Most of the seals we make go on steel strapping and PET strapping. A seal is always the same width as the band it closes, and the band decides the type: plain sleeves for steel, serrated ones for PET.
Below you can see what each finished joint looks like, and a short video of the whole job from tensioning to cutting the band.
Seals for Steel Strapping
Push, snap-on, thread-on and open-flange seals suit manual and pneumatic tools. Magazine seals feed automatic lines that bundle steel coils and wire rod. Thickness runs from 0.6 mm on 1/2 to 3/4 in sizes up to 1.2 mm on 2 in magazine seals, and high tensile strapping on heavy loads needs a longer, thicker sleeve.
Left: a notched joint on steel strapping. Right: sealing steel strapping around a coil.
Video: tensioning steel strapping and closing it with a seal.
We make these seals in the same plant as our steel strapping, so sleeve and band are matched and ship in one order.
Serrated Seals for PET Strapping
PET strapping is softer than steel, so a smooth sleeve can let it slip. Serrated seals have teeth inside that bite into the band, and embossed strapping grips better than smooth. They come in 1/2 to 3/4 in widths, are closed with a manual sealer, and work on PP strapping too. With a friction-weld or heat-seal tool, PET needs no seal at all.
A serrated seal joint on green PET strapping.
Video: tensioning PET strapping and closing it with a serrated seal.
For band widths, thicknesses and break strengths, see our PET strapping page.
Notch Joints
The tool cuts through seal and band and bends the cut edges down or up. ASTM D3953 recommends one seal with two pairs of notches, or two seals with four pairs. Notch joints are mostly used on waxed (lubricated) strapping.
Crimp Joints
The tool presses seal and band into a wave without cutting. ASTM D3953 recommends one seal with three or four pairs of crimps, or two seals with four or six pairs. Crimp joints are meant for dry heavy-duty strapping on loads that take hard knocks; on waxed strapping, add seals or crimps, or use grit-type seals.
How We Make Strapping Seals in Changzhou
JUHONG stamps strapping seals in the same Changzhou plant that makes our steel strapping, PET strapping and stretch film. Steel strip is slit to width, flattened, then punched and formed in dies into each seal type.
Strapping Seal Production: Four Stages from Steel Strip to Carton
Every seal goes through the same four stages.
Slitting
- 1Incoming checkSteel strip is checked on arrival for grade, size and surface.
- 2SlittingThe strip is cut to the blank width for each seal size.
Flattening
- 3LevelingA leveling machine flattens the strip before it enters the die.
Stamping & Forming
- 4PunchingThe die cuts the blank and forms the flanges.
- 5Press checkInspectors check parts at the punch presses with calipers against the drawing.
Inspection & Packing
- 6Coating checkZinc-coated parts go through a salt spray test and a cross-cut adhesion test.
- 7PackingSeals are counted into cartons lined with VCI anti-rust film.
The same plant also makes steel strapping, PET strapping and stretch film, so one container can carry all four.
Video: our push, open, serrated and magazine seals.
Strapping Seal Testing and Quality Control
We check every batch from raw material to shipment, against our written inspection procedures and GB/T 39040-2020, which JUHONG helped draft. See how we test on our Quality Control page.
Seal Tests We Run
These checks run on every order. Results go into the inspection report that ships with it.
| Check | How | Stage |
|---|---|---|
| Steel strip | Grade, size and surface | On arrival |
| Forming | Burrs, cracked edges and poor forming | At the punch presses |
| Dimensions | Calipers against the drawing | At the punch presses |
| Joint strength | Finished joint pulled on a tensile tester | Sampling |
| Zinc coating | 24-hour neutral salt spray and cross-cut adhesion | Zinc-coated orders |
| Final check | Size, coating, logo and carton count | Before shipment |
GB/T 39040-2020 calls for at least 3 µm of zinc per side and no red rust after 24 hours of neutral salt spray on zinc-coated seals.
SGS Test Reports and Standard for Our Seals
The cover pages of three SGS reports on our steel seals, and the national standard we helped draft. Each report covers the sample tested. Full reports are on our Downloads page.
EU RoHS
Heavy metals
Lead, mercury, cadmium and hexavalent chromium in a steel seal sample. Result: pass.
SGS XMNPC25000941905 · May 2025
EU PPWR · 2025/40
Heavy metals
Total lead, cadmium, mercury and hexavalent chromium. Result: pass.
SGS XMNPC26001225615 · May 2026
GB/T 228.1-2021
Tensile test
Tensile test on the steel of a 50 × 32 × 0.9 mm seal.
SGS XMIN2605001507ML01 · May 2026
GB/T 39040-2020
National standard
China’s standard for steel seals and edge protectors for packing. JUHONG is one of its drafting organizations.
In force since February 2021
REACH and SDS documents for our seals are available on request.
Finishes: Plain, Zinc-Coated and Logo-Stamped Seals
Plain cold rolled seals suit indoor use and normal shipping. Zinc-coated or hot-dip galvanized seals resist rust and corrosion in damp warehouses, outdoor storage and sea freight. A painted or matte finish can be made to order, and we can stamp your logo into each piece.
Drafting Organization of GB/T 39040-2020
GB/T 39040-2020 sets the requirements for steel seals and edge protectors used in packing in China. JUHONG is one of its drafting organizations, and we check our seals against it.
Packing, OEM and Bulk Supply
Most sizes are packed 1,000 to a carton; small 5/8 and 3/4 in seals go 2,000 to 5,000 to a carton. Counts for every size are in the spec sheet. We can also pack 500 or 800 to a carton, or any count you need, in neutral cartons or cartons printed with your logo. Magazine types come collated for the machine.
Cartons, Pallets and Containers
Each carton is lined with VCI anti-rust film and carries a desiccant. Cartons are stacked on fumigation-free wooden or steel pallets, wrapped, strapped and loaded by the pallet. Keep them closed, dry and off the floor until use.
Cartons
1,000 pieces for most sizes
Neutral cartons as standard, or printed with your logo. VCI film and desiccant inside.
Pallets
Wrapped and steel-strapped
Cartons are stacked, wrapped in woven cloth and strapped with steel strapping for the sea voyage.
Container
Loaded by the pallet
Pallets go into the container whole. Seal cartons can share it with our steel strapping, PET strapping and stretch film.
Sizes, carton counts and the HS code are listed in the spec sheet. Steel strapping seals ship under HS heading 7326.90.
600,000 Closed Seals in One 20GP Container
- Closed (push) seals, 53 × 32 × 0.9 mm
- 500 seals per carton
- 60 cartons on each 115 × 115 cm pallet
- 20 pallets in a 20GP container
Custom Packing and Loading Plans
We pack to your carton count, in neutral cartons or cartons printed with your logo. Every load is different, so send us the list below and we will work out a loading plan for your container.
- Seal type, size and quantity
- Carton count and printing
- Other products in the same container
- Destination port
Strapping Seal Manufacturer and Supplier for Distributors and Importers
JUHONG is a strapping seal manufacturer selling directly from the factory. Distributors and importers order seals by the carton or by the container, often together with our steel strapping and PET strapping.
Distributors and wholesalers
Buy seals by the carton or by the container.
Importers
Fill one container with seals, steel strap, PET strap and stretch film.
Tool and machine users
Get seals matched to the tool or machine you run.
Virtual showroom
Walk Through Our Sample Room in 360°
See our product samples on the shelves before you visit the plant or book a video call. The tour opens in a new tab.
Matching
Match Your Current Seal: Send a Photo
Send a photo of your seal and the jaws of your tool, or the size printed on the carton. We will match the type, width, length and thickness.
Pricing
What Changes the Price of Strapping Seals
Seal price follows the steel price, the size and thickness, the finish, logo stamping, packing and quantity. Send the size and quantity for a quotation.
OEM
Logo-Stamped Seals and Private Label Cartons
We can stamp your logo into each seal and pack it in your own cartons, at the count you need.
Mixed loads
Mixed Containers: Seals, Steel Strap, PET Strap and Stretch Film
All four products come from one plant, so you can fill one container with several of them.
From Enquiry to Repeat Order
Send your seal size or a photo. Test samples on your own tool. Confirm the size, finish and packing. Repeat orders are made to the same approved sample.
Strapping Seals & Buckles FAQ
Short answers to the questions distributors and packing managers ask us about strapping seals and buckles.
What is a strapping buckle?
It is a formed steel wire loop that joins the ends of PP or cord strapping. The band is threaded through it and tightened, and it holds without any tool.
What is the difference between a strapping seal and a buckle?
A seal is a steel sleeve that a tool presses or notches onto the band. The other is a wire loop the band is threaded through by hand. The first suits steel and polyester strapping; the second suits PP and cord strapping.
Are strapping clips and banding clips the same thing?
Yes. Strapping clips, banding clips, metal strap clips and steel seals are common names for the same part.
Which seals should I use for polyester strapping?
The serrated type, the same width as your PET strapping, closed with a manual sealer. With a friction-weld tool, nothing extra is needed.
What size seal do I need for 3/4 in strapping?
A 3/4 in (19 mm) one. Choose its length and thickness by your band thickness and tool; our 3/4 in sizes run from 22 to 57 mm long and 0.6 to 0.9 mm thick.
Do you supply wire buckles?
Yes, for PP and cord strapping. Send us your strapping type and width.
Are your seals zinc coated?
We make both plain and zinc-coated versions, including hot-dip galvanized. Coated parts go through a 24-hour salt spray test and a cross-cut adhesion test.
How are seal sizes written?
As length × width × thickness, for example 48 × 32 × 0.8 mm, where 32 mm is the strapping width it fits. GB/T 39040 writes the same seal as P0.8×32×48: type, thickness, strap width, length.
What is the HS code for strapping seals?
Steel strapping seals are classed under HS heading 7326.90 (other articles of iron or steel). We export them under China code 7326909000; check the code used in your country with your customs broker.
How many seals come in a carton?
1,000 pieces for most sizes, and 2,000 to 5,000 for small 5/8 and 3/4 in seals. We can pack 500, 800 or any count you need, in neutral or logo-printed cartons.
Get a Strapping Seal Quote
Send us your strapping width and thickness, your tool or machine model and the quantity you need. We will reply with a quotation, the matching parts and a sample plan.
- Strap width and thickness
- Steel, PET, PP or cord strap
- Tool or machine model
- Quantity and destination port
Fields marked * are required. You can attach a photo of your seal, tool or specification sheet.