This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX40S, 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 SI125BX40S
The AirTAC SI125 Standard Cylinder SI125BX40S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 40mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX40S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke40 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX40S
- 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 SI125BX40S
The AirTAC SI125BX40S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 40 mm stroke. Featuring a SUS304 stainless steel rod (-B) and a piston magnet (-S), it delivers 6136 N push force at 0.5 MPa through a G1/2 port. AirTAC replaced this legacy unit with the SAI125BX40S, a direct replacement sharing the exact ISO 15552 mounting interface, bore, stroke, and force ratings.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds SAIL and BSAI lock variants absent in the SI line. Your -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125BX40S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX40S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX40S |
| Bore size | Ø125 mm |
| Stroke | 40 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 SAI125BX40S 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 SAI125BX40S 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 SI125BX40S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×40 | 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 SI125BX40S Is Used
Heavy Stamping Press
Drives robust stamping operations requiring 6136 N of push force at 0.5 MPa, utilizing the SUS304 rod for corrosion resistance in harsh shop environments.
Pallet Diverting
Acts as a high-force diverter arm in automated warehouses, moving heavy loads reliably with a short 40 mm stroke and ISO 15552 mounting.
Injection Molding Clamp
Provides sturdy clamping force on molding fixtures, where the 125 mm bore and G1/2 port deliver rapid, high-thrust actuation.
Replacing the Airtac SI125 Standard Cylinder SI125BX40S with the SAI125BX40S
To replace the discontinued SI125BX40S, order the SAI125BX40S. It drops directly into existing fixtures via the ISO 15552 mounting interface, preserving the 125 mm bore, 40 mm stroke, M27x2 rod thread, and G1/2 port. Confirm your mounting accessory (LB, FA, TC, etc.) and thread standard (PT, G, NPT). When sizing, note the 6136 N push force at 0.5 MPa; if you need less force, a 100 mm bore provides 3927 N, while a 160 mm bore offers 10053 N. Because this plain cylinder does not hold load on air loss—the cushion only decelerates—use an external rod lock or pilot check valve for vertical loads, or specify the SAIL/BSAI lock variant. The -B SUS304 rod is ideal for corrosive settings, and Viton H seals raise the temperature range to 150 C.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX40S
- ✓ 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 SI125BX40S FAQ
Yes, the AirTAC SI125BX40S is discontinued. The direct replacement is the SAI125BX40S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 40 mm stroke, force, G1/2 port, and mounting interface.
The 125 mm bore generates a push force of 6136 N and a pull force of 5734 N at 0.5 MPa. At 0.7 MPa it pushes 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa, with an operating speed of 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX40S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX40S replacement — usually within 7-8 hours.