This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX280S, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI125 Standard Cylinder SI125BX280S
The AirTAC Airtac SI125 Standard Cylinder SI125BX280S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 280mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX280S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke280 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX280S
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI125 Standard Cylinder SI125BX280S
The AirTAC SI125BX280S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125mm bore, 280mm stroke, and a SUS304 stainless piston rod. It delivers 6136 N push force at 0.5 MPa and uses a G1/2 air port. AirTAC replaced this legacy unit with the SAI125BX280S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, stroke, and output force.
The SAI replacement upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI family introduces SAIL lock and BSAI clamp-lock variants absent in the SI line.
Airtac SI125 Standard Cylinder SI125BX280S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX280S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX280S |
| Bore size | Ø125 mm |
| Stroke | 280 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125BX280S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125BX280S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125BX280S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×280 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI125 Standard Cylinder SI125BX280S Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136 N push force at 0.5 MPa to hold components firmly against the fixture.
Pallet Diverting
Actuates heavy-duty lane diverters in distribution centers, where the 313 kg vertical lift capacity and 280mm stroke easily redirect loaded pallets.
Stamping Ejection
Ejects dense stamped parts from hydraulic presses, relying on the SUS304 stainless rod to resist corrosion in lubricant-rich environments.
Replacing the Airtac SI125 Standard Cylinder SI125BX280S with the SAI125BX280S
To replace the SI125BX280S, order the SAI125BX280S, confirming the ISO 15552 mounting interface, 280mm stroke, G1/2 port, and the -S magnet for current AirTAC switches. If downsizing, an 80mm bore yields 2513 N push at 0.5 MPa; if upsizing, a 160mm bore provides 10053 N. Note that a plain cylinder drifts on air loss as the 40mm adjustable cushion only decelerates the load. For load holding, specify the SAIL or BSAI lock variant, or use an external pilot check valve. Because the 280mm stroke exceeds 300mm? No, at 280mm side-load risks are moderate, but always guide the rod to prevent bending. The -B rod option provides SUS304 stainless steel for corrosion resistance.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX280S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125BX280S FAQ
Yes, the AirTAC SI125BX280S is discontinued. The direct replacement is the SAI125BX280S. It features the same ISO 15552 mounting interface, 125mm bore, 280mm stroke, G1/2 port, and output force, fitting existing fixtures perfectly without modifications.
The 125mm bore uses a G1/2 air port. Force output is 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical maximum of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX280S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX280S replacement — usually within 7-8 hours.