This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX20S, 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 SI125AX20S
The AirTAC SI125 Standard Cylinder SI125AX20S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 20mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX20S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke20 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX20S
- 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 SI125AX20S
The AirTAC SI125AX20S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 20 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125AX20S, featuring a SUS420J2 stainless rod and matching G1/2 port.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL and BSAI lock variants absent in the SI line.
Airtac SI125 Standard Cylinder SI125AX20S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX20S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX20S |
| Bore size | Ø125 mm |
| Stroke | 20 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 SAI125AX20S 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 SAI125AX20S 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 SI125AX20S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×20 | 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 SI125AX20S Is Used
Heavy Pressing
Applies 6136 N of thrust at 0.5 MPa for seating bearings or forming components in automated machinery.
Pallet Diverter
Short 20 mm stroke delivers rapid plunger actuation to redirect heavy pallets on a packaging line.
Clamp Actuation
Provides high clamping force for securing large work-holding fixtures during machining operations.
Replacing the Airtac SI125 Standard Cylinder SI125AX20S with the SAI125AX20S
To replace the SI125AX20S, order the SAI125AX20S. It is dimensionally interchangeable per the ISO 15552 mounting interface, keeping the 125 mm bore, 20 mm stroke, G1/2 port, and M27x2 thread. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. If you need more force, the 160 mm bore offers 10053 N at 0.5 MPa; if less is needed, the 100 mm bore provides 3927 N. For load holding on air loss, note that a plain cylinder drifts and the 40 mm cushion only decelerates—use an external rod lock or pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX20S
- ✓ 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 SI125AX20S FAQ
Yes, the SI125AX20S is discontinued. The direct replacement is the SAI125AX20S. It shares the same ISO 15552 mounting interface, 125 mm bore, 20 mm stroke, force, and G1/2 port, fitting existing fixtures perfectly.
It has a G1/2 port. The force ratings are: 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 max of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX20S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX20S replacement — usually within 7-8 hours.