This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX280, 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 SI125BX280
The AirTAC Airtac SI125 Standard Cylinder SI125BX280 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 SAI125BX280, 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 → SAI125BX280
- 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 SI125BX280
The AirTAC SI125BX280 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore and 280 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125BX280, matching the interface, G1/2 port, and output. The SAI upgrades the piston seal to two Y-shaped one-way elements for low start-up pressure and long life. This -B variant has a SUS304 stainless rod for corrosion resistance. Lacking the -S suffix, this SKU cannot take a sensor.
The SAI family also introduces SAIL and BSAI lock variants absent in the SI line. Note that a plain cylinder drifts without live air; the cushion only decelerates.
Airtac SI125 Standard Cylinder SI125BX280 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX280 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX280 |
| 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 SAI125BX280 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 SAI125BX280 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 SI125BX280
| 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 SI125BX280 Is Used
Heavy Press Stamping
Drives large metal forming presses requiring 6136 N push force at 0.5 MPa to stamp thick automotive panels.
Mould Clamping Fixtures
Secures heavy injection moulds via the ISO 15552 mounting interface, utilizing the 280 mm stroke for wide openings.
Replacing the Airtac SI125 Standard Cylinder SI125BX280 with the SAI125BX280
To replace the SI125BX280, order the SAI125BX280. It is dimensionally interchangeable per ISO 15552, keeping the 125 mm bore, 280 mm stroke, 6136 N force, G1/2 port, and mounting. Confirm the -B SUS304 stainless rod and note this no-magnet SKU cannot accept a CS1-B or DS1-B sensor. For sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. For load holding, a plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 280 mm stroke, ensure guide rails carry side loads to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX280
- ✓ 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 SI125BX280 FAQ
Yes, the SI125BX280 is discontinued. The direct replacement is the SAI125BX280. It is dimensionally interchangeable per ISO 15552, offering the same 125 mm bore, 280 mm stroke, force, G1/2 port, and mounting interface, but features an upgraded piston seal.
This double-acting cylinder has a G1/2 port, M27x2 rod thread, and 40 mm cushions. It delivers 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, and a theoretical max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX280
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX280 replacement — usually within 7-8 hours.