This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX275S, 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 SI125AX275S
The AirTAC SI125 Standard Cylinder SI125AX275S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 275mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX275S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke275 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX275S
- 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 SI125AX275S
The AirTAC SI125AX275S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore, 275mm stroke, SUS420J2 stainless rod (-A), and piston magnet (-S). Delivering 6136 N push force at 0.5 MPa, it features a G1/2 port, M27x2 rod thread, and 40mm adjustable cushions. The direct replacement is the SAI125AX275S, sharing the same interface, force, and mounting.
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, SAIF, and BSAI lock variants the SI lacked. This -S SKU uses CS1-B/DS1-B sensors; the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125AX275S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX275S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX275S |
| Bore size | Ø125 mm |
| Stroke | 275 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 SAI125AX275S 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 SAI125AX275S 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 SI125AX275S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×275 | 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 SI125AX275S Is Used
Heavy Press Clamping
Generates 6136 N at 0.5 MPa to secure heavy metal workpieces in machining fixtures, utilizing the SUS420J2 stainless rod for corrosion resistance in coolant environments.
Automated Forming Press
Drives large forming tools with 8590 N at 0.7 MPa, relying on the 40mm adjustable air cushions to decelerate heavy tooling masses smoothly at stroke ends.
Replacing the Airtac SI125 Standard Cylinder SI125AX275S with the SAI125AX275S
To replace the SI125AX275S, order the SAI125AX275S: verify the ISO 15552 mounting interface, 125mm bore, 275mm stroke, G1/2 port (PT/G/NPT), and mounting accessory. The -A rod is SUS420J2 stainless steel, and the -S magnet works with CS1-B/DS1-B switches. Sizing both ways: at 0.5 MPa it pushes 6136 N (neighbour bore 100 pushes 3927 N; bore 160 pushes 10053 N). For 275mm strokes, ensure guide alignment to prevent rod bending and side-load wear. A plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX275S
- ✓ 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 SI125AX275S FAQ
Yes, the AirTAC SI125AX275S is discontinued. The direct replacement is the SAI125AX275S. It is dimensionally interchangeable per ISO 15552, retaining the same 125mm bore, 275mm stroke, 6136 N force, G1/2 port, and mounting interface.
It has a G1/2 port. The force ratings are: push 6136 N and pull 5734 N at 0.5 MPa; push 8590 N at 0.7 MPa; push 11045 N at 0.9 MPa; with 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 SAI125AX275S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX275S replacement — usually within 7-8 hours.