This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX275, 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 SI125AX275
The AirTAC SI125 Standard Cylinder SI125AX275 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 SAI125AX275, 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 → SAI125AX275
- 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 SI125AX275
The AirTAC SI125AX275 is a discontinued double-acting ISO 15552 profile cylinder featuring an extruded aluminum barrel and a SUS420J2 stainless piston rod. Built for heavy loads, it delivers 6136 N push and 5734 N pull at 0.5 MPa. The direct replacement is the SAI125AX275, which matches the exact bore, stroke, port, and mounting interface. The SAI upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life.
Because this SKU lacks the -S magnet, it cannot accept a position sensor. The G1/2 port and 40 mm cushions remain unchanged. If high-temperature operation is needed, the Viton H seal option extends the range to 0-150 C.
Airtac SI125 Standard Cylinder SI125AX275 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX275 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX275 |
| 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 SAI125AX275 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 SAI125AX275 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 SI125AX275
| 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 SI125AX275 Is Used
Heavy Stamping Press
Drives large dies and platens requiring 8590 N push force at 0.7 MPa, utilizing the 40 mm adjustable cushions to absorb end-of-stroke impact.
Automated Assembly Fixture
Clamps heavy structural components during multi-stage fastening, relying on the ISO 15552 profile barrel for rigid fixture mounting.
Replacing the Airtac SI125 Standard Cylinder SI125AX275 with the SAI125AX275
To replace this SI125AX275, order the SAI125AX275. It is dimensionally interchangeable per the ISO 15552 mounting interface, keeping the 125 mm bore, 275 mm stroke, G1/2 port, and M27x2 rod thread. Confirm your mounting accessory (LB, FA, TC, etc.) and note that this no-magnet version cannot use CS1-B/DS1-B sensors. When sizing, neighboring bores offer different force classes: the 100 mm bore provides 3927 N push at 0.5 MPa, while the 160 mm bore yields 10053 N. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, a pilot check valve, or the SAIL/BSAI lock variants. Since the 275 mm stroke exceeds 300 mm? No, but for any stroke near this length, ensure adequate guide support to prevent rod bending under side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX275
- ✓ 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 SI125AX275 FAQ
Yes, the SI125AX275 is discontinued. The direct replacement is the SAI125AX275. It shares the identical ISO 15552 mounting interface, 125 mm bore, 275 mm stroke, force, and G1/2 port, fitting existing fixtures perfectly.
It operates at 0.15-1.0 MPa (proof 1.5 MPa) with a speed of 30-500 mm/s. Force output is 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 maximum of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX275
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX275 replacement — usually within 7-8 hours.