The main difference between 202 RPT (Ring Pull Tab) and 202 SOT (Stay-On Tab) easy open ends is what happens to the tab after opening. RPT detaches completely; SOT stays attached to the lid. Both are stamped from 5182-H48 aluminum alloy, but SOT tabs are slightly thicker (0.310 mm vs 0.290 mm) and need a higher pop force (≤24 N vs ≤22 N) and tear force (≤33 N vs ≤28 N).
1. How RPT and SOT Tabs Actually Work
When you pull a 202 RPT end, the ring acts as a first-class lever. It lifts the scored panel out of the lid and the whole tab detaches. That gives a wide, clean opening, but the tab becomes a separate piece of waste.
A 202 SOT end works differently. The tab is riveted at the center and acts as a second-class lever. When you lift the ring, the nose of the tab pushes the scored panel down into the can. The tab itself stays attached to the lid. This is why SOT ends meet anti-littering rules in the EU, UK, and an increasing number of US states.
The thicker SOT tab (0.310 mm) and deeper countersink (1.30–1.35 mm) also give it a slightly higher buckle pressure rating. For carbonated products that go through tunnel pasteurization or hot-fill-and-hold, that extra margin matters.
2. Hardcore Technical Matrix: Micro-Dimension and Tear Force Tolerances
When you are choosing between 202 RPT and 202 SOT ends, the spec sheet is what your line engineer and procurement team will both look at. Below is the side-by-side data we use at Alucan to match ends to can bodies and filling lines:
| Parameter | 202 RPT | 202 SOT | Notes |
|---|---|---|---|
| Alloy / temper | 5182-H48 | 5182-H48 | Same base stock; SOT rivet area may be slightly harder |
| Tab thickness | 0.290 ± 0.005 mm | 0.310 ± 0.003 mm | Thicker SOT tab resists buckling during lever action |
| Countersink depth | 1.20 mm | 1.30–1.35 mm | Depends on whether CDL or B64 profile is used |
| Pop force | ≤ 22 N | ≤ 24 N | Initial force to break the score |
| Tear force | ≤ 28 N | ≤ 33 N | Force to fully open the aperture |
| Buckle pressure | ≥ 6.0 bar | ≥ 6.2 bar | Higher rating helps in pasteurization |
| Tab after opening | Detached | Stays on lid | Key factor in anti-littering rules |
3. Line Setup: Why You Cannot Mix RPT and SOT on the Same Run
RPT and SOT ends look similar from a distance, but their tab profiles are different enough that a seamer feed system cannot sort them reliably. An RPT tab lies flatter and has a shorter tail. An SOT tab is longer, curves upward, and has a wider nose. If you load a mixed batch, the feed chute will jam and the pocket separation pins will either crush SOT tabs or drop RPT tabs.
This means your whole production run for a given SKU must use one tab type. Switching from RPT to SOT requires:
- Feed chute width adjustment: SOT tabs need slightly more clearance because of the curved tail.
- Pocket separation pins: the pin spacing and height must match the tab thickness and tail length.
- Orientation track: SOT tabs are handed; the feed track must present the tab nose in the correct direction.
- Seamer chuck: if you use the same 202 neck profile, the chuck does not change, but the cap-feed timing may need adjustment.
On Angelus and Ferrum seamers, the changeover is usually a 20–40 minute job once the spare parts are on hand. The bigger cost is keeping both sets of feed tooling in inventory if you run mixed contracts.
4. Internal Linings for RPT and SOT Ends
The end's internal lining covers the metal surface that touches the beverage. A thin spot or skipped area around the score line, rivet, or panel edge can let product reach bare aluminum, causing metallic off-flavors or corrosion. This is why we run a high-voltage copper-sulfate porosity test on every batch before shipment.
Both RPT and SOT ends can use the same two coating tracks:
The coating choice is usually driven by the destination market, not the tab type. However, high-acid or high-carbonation products put more stress on the liner, so we may recommend a higher coat weight regardless of whether you choose RPT or SOT.
5. Regional Regulatory Trends: Anti-Littering and Deposit Return Schemes
Tab design is no longer purely an engineering decision; it is increasingly a compliance decision. Many jurisdictions now restrict removable tabs to reduce litter in marine and outdoor environments. Key regional frameworks include:
- European Union: SOT ends dominate mainstream beverage cans across the EU, aligning with Extended Producer Responsibility (EPR) schemes and deposit-return systems (DRS).
- United Kingdom: Major retailers and brewers specify SOT for own-label and premium brands to meet sustainability commitments and DRS readiness.
- North America: Both RPT and SOT coexist, though California and several coastal states show accelerating preference for SOT in single-serve packaging.
- Australia and New Zealand: Container deposit legislation and anti-litter campaigns favor SOT, particularly for products sold through outdoor and event channels.
6. Opening Force Testing and Quality Validation
The numbers on the spec sheet only matter if they are measured consistently. At Alucan, every end lot is sampled for pop force, tear force, and buckle pressure before shipment. A typical report shows the mean, minimum, and maximum for each measurement, plus the AQL level used for acceptance.
For RPT ends, the score line is optimized for a single clean pull, so the pop force is lower and the tear profile is more linear. For SOT ends, the rivet and thicker tab create a higher initial peak, and the tear force stays elevated through the full opening. Both profiles are valid; what matters is that the readings fall within the agreed tolerance band and match your seamer and consumer expectations.
| Test | 202 RPT typical range | 202 SOT typical range | Why it matters |
|---|---|---|---|
| Pop force | ≤ 22 N | ≤ 24 N | Ease of first opening |
| Tear force | ≤ 28 N | ≤ 33 N | Force to complete aperture |
| Buckle pressure | ≥ 6.0 bar | ≥ 6.2 bar | Pasteurization safety margin |
| Coating porosity | Zero pinholes | Zero pinholes | Prevents corrosion and off-flavors |
If you are qualifying a new end supplier, ask for a full force-test report and a coating porosity certificate. These two documents tell you more about real-world performance than a drawing alone.
7. End-of-Life, Recycling, and Sustainability Considerations
Aluminum is infinitely recyclable, but end design affects downstream sorting and recycling economics. Because SOT tabs remain attached to the lid, they travel through the recycling stream as a single piece, simplifying eddy-current separation and reducing contamination risk. Removable RPT tabs can detach during collection and transport, potentially entering wrong material streams or becoming visible litter.
For brands marketing circular-economy credentials, specifying SOT ends supports recycling-rate claims and reduces the risk of regulatory penalties in jurisdictions with strict packaging waste directives. Alucan provides certification documentation linking SOT end specifications to regional recycling targets upon request.
8. Frequently Asked Questions
Can you run 202 RPT and 202 SOT ends on the same seaming line?
No, not in the same production run. The tab thickness, tail length, and curvature are different, so a mixed feed will jam the cap-feed chute and damage the pocket separation pins. You can run both formats on the same seamer, but only after a tooling changeover.
Which is better for carbonated beverages, RPT or SOT?
SOT is generally better for carbonated beverages because the thicker tab and deeper countersink give a higher buckle pressure margin. SOT also meets anti-littering rules in the EU, UK, and several US states.
What is the difference between RPT and SOT easy open ends?
RPT (Ring Pull Tab) detaches completely from the lid when opened. SOT (Stay-On Tab) stays attached to the lid through a central rivet. SOT tabs are slightly thicker and require a higher pop and tear force.
Do RPT and SOT ends use the same internal coating?
Yes. Both can use BPANI or Epoxy-Phenolic linings. The choice depends on your destination market and beverage chemistry, not the tab type.
How do you test pop force and tear force on RPT and SOT ends?
We use calibrated force gauges on a sample lot. Pop force is the initial break of the score, and tear force is the pull needed to complete the opening. RPT ends typically read lower on both measurements because the tab is thinner and the score line is designed for a clean pull. SOT ends read higher because the thicker tab and stay-on rivet need more leverage. Each report includes the mean, range, and AQL acceptance level.
Which end type is better for food-contact safety and compliance?
Both RPT and SOT ends can be produced with BPANI or Epoxy-Phenolic linings. Food-contact safety depends on the coating choice and your destination market, not the tab geometry. North America and the EU usually require BPA-NI formulations, while other markets may still accept Epoxy-Phenolic. We supply migration test reports and certificates of compliance on request.
What should I ask my OEM supplier before choosing RPT or SOT?
Ask for tab force test data, buckle pressure documentation, coating compliance certificates, and seamer chuck compatibility confirmation. Also confirm the supplier can keep RPT and SOT tooling separate in the same shipment if you plan to run both formats.
9. RPT vs SOT Decision Guide
Use this checklist to choose the right tab type for your next order:
- Choose SOT if: your target market is the EU, UK, Australia, or any region with anti-littering or deposit-return rules; your beverage is carbonated or pasteurized; you want the tab to stay attached for recycling stream simplicity.
- Choose RPT if: your market still accepts removable tabs; your product is non-carbonated, such as still water, wine, or juice; your customers prefer the wide opening and familiar pull of a ring-pull tab.
- Do not mix: never run RPT and SOT ends through the same seamer feed chute in the same shift. The tab shapes are too different for reliable sorting.
10. Sourcing RPT and SOT Ends from Alucan
If you are unsure which tab type fits your market and line, send us your product specification and destination country. We will confirm the regulatory requirement, recommend the right lining, and ship a dual-tab sample kit with pop-force and tear-force reports so your line engineer can test both profiles before you order.
Need RPT or SOT can end samples?
Contact Christine Wong for a dual-tab testing kit with pop-force, tear-force, and coating compliance reports.
Request Free Samples →