This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX125, 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 SI40BX125
The AirTAC Airtac SI40 Standard Cylinder SI40BX125 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 SAI40BX125, 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 → SAI40BX125
- 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 SI40BX125
The AirTAC SI40BX125 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 125mm stroke, and a SUS304 stainless steel piston rod. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40BX125, matching the bore, stroke, force, port, and ISO 15552 mounting interface.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. Note this SKU lacks a magnet, so it cannot take a CS1-B/DS1-B sensor.
Airtac SI40 Standard Cylinder SI40BX125 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX125 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX125 |
| 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 SAI40BX125 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 SAI40BX125 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 SI40BX125
| 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 SI40BX125 Is Used
Stainless Rod Actuation
Ideal for moderate push loads requiring the SUS304 corrosion-resistant rod option in washdown or humid manufacturing cells.
Line Diverting
Provides reliable 125mm stroke diverting force on packaging lines, utilizing the 628N thrust at 0.5MPa.
Gate Control
Drives lightweight access gates or material stops where a true ISO 15552 mounting footprint is already fixtured.
Replacing the Airtac SI40 Standard Cylinder SI40BX125 with the SAI40BX125
To replace the SI40BX125, order the SAI40BX125. Verify the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port, and the M12x1.25 rod thread. Because this is a no-magnet SKU, it cannot accept position sensors; order a magnet-equipped SAI if sensing is needed. Sizing both ways: a 32mm bore yields 402N @0.5MPa, while a 50mm bore yields 982N @0.5MPa. For load holding on air loss, the cushion only decelerates; add an external pilot check valve or choose the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX125
- ✓ 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 SI40BX125 FAQ
Yes, the SI40BX125 is discontinued. The direct replacement is the SAI40BX125. It is dimensionally interchangeable per the ISO 15552 mounting interface, retaining the same 40mm bore, 125mm stroke, 628N force, and G1/4 port.
The G1/4 port feeds a 40mm bore yielding 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N at 0.9MPa, and a max force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX125
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX125 replacement — usually within 7-8 hours.