This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX375S, 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 SI125BX375S
The AirTAC SI125 Standard Cylinder SI125BX375S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 375mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX375S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke375 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX375S
- 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 SI125BX375S
The AirTAC SI125BX375S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 375mm stroke. It delivers 6136N push and 5734N pull at 0.5MPa, utilizing a SUS304 stainless piston rod for corrosion resistance and a built-in magnet for CS1-B/DS1-B sensors. AirTAC replaced this legacy unit with the SAI125BX375S, a direct sharing the same G1/2 port, M27x2 thread, and mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, explore the SAIL or BSAI lock variants, or use an external pilot check valve.
Airtac SI125 Standard Cylinder SI125BX375S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX375S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX375S |
| Bore size | Ø125 mm |
| Stroke | 375 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 SAI125BX375S 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 SAI125BX375S 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 SI125BX375S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×375 | 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 SI125BX375S Is Used
Heavy Stamping Press
Drives heavy tooling with 6136N push at 0.5MPa, utilizing the adjustable 40mm air cushions to decelerate the 375mm stroke smoothly.
Large Component Transfer
Shifts heavy automotive casts along the 375mm travel, requiring external guide rails to prevent rod bending during the move.
Replacing the Airtac SI125 Standard Cylinder SI125BX375S with the SAI125BX375S
To replace the SI125BX375S, order the SAI125BX375S. Confirm the ISO 15552 mounting interface (LB, FA, TC, etc.), the G1/2 port, and the -S magnet for legacy CS1-B/DS1-B switches (the SAI uses current AirTAC switches). The SUS304 rod (-B) is essential for wet environments. Sizing both ways: this 125mm bore yields 6136N push at 0.5MPa; if oversizing, an 80mm bore provides 2513N, while a 160mm bore offers 10053N. Because the 375mm stroke is long, use external guides to prevent rod bending and side-load wear. For dead-load holding, the standard cylinder lacks a brake—select the SAIL air-released lock or BSAI clamp-lock variant, or add an external rod lock.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX375S
- ✓ 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 SI125BX375S FAQ
Yes, the SI125BX375S is discontinued. The direct replacement is the SAI125BX375S. It shares the exact same ISO 15552 mounting interface, 125mm bore, 375mm stroke, G1/2 port, and output force, fitting existing fixtures perfectly. The SAI features an upgraded piston seal for longer life.
The 125mm bore generates 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. Operating speed is 30-500mm/s. It features a G1/2 port, M27x2 rod thread, and 40mm adjustable cushions at both ends.
Related AirTAC SAI Cylinders
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