This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX275, 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 SI125BX275
The AirTAC SI125 Standard Cylinder SI125BX275 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 SAI125BX275, 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 → SAI125BX275
- 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 SI125BX275
The AirTAC SI125BX275 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125mm bore, 275mm stroke, and a SUS304 stainless steel rod. Delivering 6136N push force at 0.5MPa, it is replaced by the SAI125BX275. This direct successor shares the exact G1/2 port, M27x2 thread, and mounting interface, fitting existing fixtures seamlessly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and longevity. For this non-magnet SKU, position sensing is impossible; legacy switches like CS1-B are incompatible. The family also adds SAIL lock, SAIF valve, and BSAI clamp variants the SI lacked.
Airtac SI125 Standard Cylinder SI125BX275 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX275 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX275 |
| 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 SAI125BX275 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 SAI125BX275 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 SI125BX275
| 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 SI125BX275 Is Used
Heavy Press Operations
Drives substantial forming and stamping presses using 6136N thrust at 0.5MPa, with the SUS304 rod resisting corrosion in humid production environments.
Large Clamp Fixtures
Secures heavy fabricated components during machining, relying on the 125mm bore's 5734N pull force and 40mm adjustable cushions to absorb shock.
Replacing the Airtac SI125 Standard Cylinder SI125BX275 with the SAI125BX275
To replace the SI125BX275, order the SAI125BX275, confirming the ISO 15552 interface, 125mm bore, 275mm stroke, G1/2 port, and SUS304 rod. Size both ways: a 100mm bore yields 3927N push at 0.5MPa, while a 160mm bore yields 10053N. At 275mm stroke, use guide rails to prevent rod bending and side-load wear. This SKU lacks a magnet, so it cannot accept CS1-B/DS1-B sensors. The air cushion only decelerates; it does not hold load on air loss. For secure holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX275
- ✓ 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 SI125BX275 FAQ
Yes, the SI125BX275 is discontinued. The direct replacement is the SAI125BX275. It shares the same ISO 15552 mounting interface, 125mm bore, 275mm stroke, force, and G1/2 port, fitting directly into your existing fixtures.
It features a G1/2 air port and M27x2 rod thread. Force ratings are: 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical max of 1251kgf at 1.0MPa. Speed is 30-500mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX275
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX275 replacement — usually within 7-8 hours.