This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X275S, 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 SI125X275S
The AirTAC SI125 Standard Cylinder SI125X275S 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 SAI125X275S, 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 → SAI125X275S
- 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 SI125X275S
The AirTAC SI125X275S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 275 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. Because 275 mm is a non-standard stroke, verify dimensions before ordering. AirTAC replaced this unit with the SAI125X275S, a direct upgrade sharing the exact ISO 15552 mounting interface, M27x2 rod thread, and 40 mm cushions.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also introduces SAIL and BSAI lock variants absent in the SI line. Your -S magnet works with legacy CS1-B/DS1-B sensors, though SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X275S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X275S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X275S |
| 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 SAI125X275S 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 SAI125X275S 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 SI125X275S
| 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 SI125X275S Is Used
Heavy Press Clamping
Generates 6136 N at 0.5 MPa to secure heavy metalwork in machining fixtures, utilizing the adjustable 40 mm cushions to absorb end-of-stroke impact.
Bulk Material Diversion
Shifts heavy aggregate or component diverters on high-throughput lines, where the 125 mm bore handles high inertial loads without stalling.
Replacing the Airtac SI125 Standard Cylinder SI125X275S with the SAI125X275S
To replace the SI125X275S, order the SAI125X275S. Confirm the ISO 15552 mounting interface, G1/2 port, and your specific mounting accessory (LB, FA, TC, etc.). The -S magnet allows sensor use. Sizing both ways: the 125 mm bore yields 6136 N push at 0.5 MPa; if less force is needed, an 80 mm bore provides 2513 N. Because 275 mm is non-standard, ensure it matches your fixture. For strokes over 300 mm, guide the load 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 pilot check valve or the SAIL/BSAI lock variant. Note: bores 125-200 operate at 30-500 mm/s.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X275S
- ✓ 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 SI125X275S FAQ
Yes, the SI125X275S is discontinued. The direct replacement is the AirTAC SAI125X275S. It shares the exact ISO 15552 mounting interface, 125 mm bore, 275 mm stroke, force, G1/2 port, and accessories, fitting directly into existing fixtures.
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. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X275S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X275S replacement — usually within 7-8 hours.