This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX400S, 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 SI125AX400S
The AirTAC SI125 Standard Cylinder SI125AX400S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX400S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX400S
- 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 SI125AX400S
The AirTAC SI125AX400S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 400mm stroke. Featuring a SUS420J2 stainless steel rod and a built-in magnet for CS1-B/DS1-B sensors, it delivers 6136N push force at 0.5MPa via a G1/2 port. The direct replacement is the SAI125AX400S, matching the exact interface, force, and mounting.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. For load holding, note that standard cylinders drift on air loss; the cushion only decelerates. Use the SAIL or BSAI lock variants, or external checks.
Airtac SI125 Standard Cylinder SI125AX400S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX400S |
| Bore size | Ø125 mm |
| Stroke | 400 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 SAI125AX400S 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 SAI125AX400S 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 SI125AX400S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×400 | 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 SI125AX400S Is Used
Heavy Stamping Press
Drives heavy tooling in automated stamping lines, utilizing the 11045N push force at 0.9MPa to form thick gauge metal components reliably.
Injection Mould Clamp
Secures large mould halves using the 125mm bore power class, requiring external guide rods to manage side loads over the 400mm stroke.
Replacing the Airtac SI125 Standard Cylinder SI125AX400S with the SAI125AX400S
To replace the SI125AX400S, order the SAI125AX400S. Verify the ISO 15552 mounting interface, 125mm bore, 400mm stroke, G1/2 port, and the -S magnet for legacy CS1-B/DS1-B sensors (the SAI uses current AirTAC switches). The -A suffix indicates a SUS420J2 stainless rod, ideal for corrosion resistance versus standard carbon steel. If sizing alternatives, neighbouring bores or the 8590N push force at 0.7MPa provide scaling headroom. For this 400mm stroke, use external guides to prevent rod-bending and side-load damage. Because a plain cylinder does not hold load without live air, select the SAIL or BSAI lock variant, or an external pilot check valve for vertical loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX400S
- ✓ 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 SI125AX400S FAQ
Yes, the SI125AX400S is discontinued. The direct replacement is the SAI125AX400S. It is dimensionally interchangeable per ISO 15552, keeping the same 125mm bore, 400mm stroke, G1/2 port, and mounting interface.
The bore is 125mm with a G1/2 air port. The thrust is 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical maximum of 1251 kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX400S replacement — usually within 7-8 hours.