This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX125, 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 SI125BX125
The AirTAC SI125 Standard Cylinder SI125BX125 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 125mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX125, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke125 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX125
- 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 SI125BX125
The AirTAC SI125BX125 is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 125mm stroke. Delivering 6136 N push force at 0.5 MPa, it features a SUS304 stainless piston rod (-B) for corrosion resistance and a G1/2 air port. This SKU lacks a magnet and cannot support sensing.
The direct replacement is the SAI125BX125, sharing the exact ISO 15552 mounting interface, output force, and porting. The SAI upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure.
Airtac SI125 Standard Cylinder SI125BX125 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX125 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX125 |
| Bore size | Ø125 mm |
| Stroke | 125 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 SAI125BX125 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 SAI125BX125 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 SI125BX125
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | 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 SI125 Standard Cylinder SI125BX125 Is Used
Heavy Press Clamping
Secures large steel plates in machining centers using the full 6136 N push force, with the SUS304 rod resisting coolant corrosion.
Injection Mold Ejection
Drives robust ejection pins in plastic molding lines, relying on the 40 mm adjustable air cushions to decelerate heavy tooling.
Replacing the Airtac SI125 Standard Cylinder SI125BX125 with the SAI125BX125
To replace the SI125BX125, order the SAI125BX125 and confirm your ISO 15552 mounting accessory (LB, FA, TC, etc.) and G1/2 port threads (PT, G, or NPT). Because this specific SKU has no -S magnet, it cannot accept a CS1-B or DS1-B sensor; if position detection is required, switch to a magnet-equipped SAI model. Sizing both ways: a 125mm bore yields 6136 N push at 0.5 MPa (8590 N at 0.7 MPa), while a neighbouring 100mm bore provides 3927 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX125
- ✓ 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 SI125BX125 FAQ
Yes, the SI125BX125 is end-of-life. The direct replacement is the SAI125BX125. It is dimensionally interchangeable per ISO 15552, retaining the same 125mm bore, 125mm stroke, G1/2 port, and mounting interface to fit existing fixtures directly.
This cylinder uses a G1/2 air port. At 0.5 MPa it provides 6136 N push and 5734 pull force. This increases to 8590 N push at 0.7 MPa and 11045 N push at 0.9 MPa, with a theoretical maximum of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX125
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX125 replacement — usually within 7-8 hours.