This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X125S, 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 SI40 Standard Cylinder SI40X125S
The AirTAC Airtac SI40 Standard Cylinder SI40X125S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X125S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X125S
- 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 SI40 Standard Cylinder SI40X125S
The AirTAC SI40X125S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 125mm stroke. Delivering 628N push force at 0.5MPa through a G1/4 port, it is replaced by the SAI40X125S. This direct upgrade shares the exact ISO 15552 mounting interface, bore, stroke, force, port and accessories, fitting existing fixtures perfectly.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. It also introduces SAIL, SAIF, and BSAI lock variants the SI lacked. The -S suffix denotes a piston magnet for legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40X125S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X125S |
| Bore size | Ø40 mm |
| Stroke | 125 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X125S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X125S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X125S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×125 | 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 SI40 Standard Cylinder SI40X125S Is Used
Component Clamping
Ideal for securing mid-weight workpieces during machining, utilizing its 628N push force to hold parts firmly against stops.
Package Diverting
Deploys a 125mm stroke to push cartons or totes between adjacent conveyor lines smoothly and reliably.
Replacing the Airtac SI40 Standard Cylinder SI40X125S with the SAI40X125S
To replace the SI40X125S, order the SAI40X125S. Verify the ISO 15552 mounting interface, 125mm stroke, G1/4 port (PT/G/NPT thread), M12x1.25 rod thread, and your mounting accessory. The -S magnet is present for position sensing. For sizing, a 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N; choose based on your exact load. Note that 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 variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X125S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X125S FAQ
Yes, the SI40X125S is discontinued. The direct replacement is the SAI40X125S. It shares the same ISO 15552 mounting interface, 40mm bore, 125mm stroke, output force, G1/4 port, and mounting accessories, fitting directly into existing fixtures.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a maximum theoretical force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X125S replacement — usually within 7-8 hours.