This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX325S, 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 SI125AX325S
The AirTAC SI125 Standard Cylinder SI125AX325S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 325mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX325S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke325 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX325S
- 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 SI125AX325S
The AirTAC SI125AX325S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 325 mm stroke. It delivers 6136 N push and 5734 N pull at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125AX325S, which matches the original bore, stroke, force, port, and ISO 15552 mounting interface for existing fixtures.
This SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The SI line lacked the SAIL air-released lock, SAIF built-in valve, and BSAI clamp-lock variants now available. The SUS420J2 stainless rod and Viton H high-temp seal options provide extra durability.
Airtac SI125 Standard Cylinder SI125AX325S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX325S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX325S |
| Bore size | Ø125 mm |
| Stroke | 325 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 SAI125AX325S 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 SAI125AX325S 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 SI125AX325S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×325 | 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 SI125AX325S Is Used
Heavy Press Clamping
Generates 8590 N at 0.7 MPa to secure large metal castings during machining operations.
Large Mold Ejection
Ejects heavy industrial molds over the 325 mm travel distance with stable force.
Replacing the Airtac SI125 Standard Cylinder SI125AX325S with the SAI125AX325S
To replace the SI125AX325S, order the SAI125AX325S. Confirm the ISO 15552 mounting interface, 325 mm stroke, G1/2 port, and the -S magnet for CS1-B/DS1-B legacy sensors (the SAI uses current AirTAC switches). If you need more force than the 6136 N at 0.5 MPa, step up to a 160 mm bore; if less is required, an 80 mm bore provides 2513 N. For this 325 mm stroke, use external guides to prevent rod bending and side-load damage. A plain cylinder drifts without live air, so for load holding choose the SAIL or BSAI lock variant, or use an external rod lock.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX325S
- ✓ 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 SI125AX325S FAQ
Yes, the SI125AX325S is discontinued. The direct replacement is the SAI125AX325S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 325 mm stroke, output force, G1/2 port, and mounting accessories.
The 125 mm bore provides 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N at 0.9 MPa, and a theoretical max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s. It features a 32 mm rod, M27x2 thread, and 40 mm cushions.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX325S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX325S replacement — usually within 7-8 hours.