This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX250, 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 SI125BX250
The AirTAC SI125 Standard Cylinder SI125BX250 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 250mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX250, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke250 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX250
- 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 SI125BX250
The AirTAC SI125BX250 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 250 mm stroke. It delivers a 6136 N push force at 0.5 MPa and features a SUS304 stainless steel piston rod for corrosion resistance. As this SKU lacks a magnet, it cannot accept position sensors. The direct replacement is the SAI125BX250, retaining the identical G1/2 port, M27x2 thread, and ISO 15552 mounting interface.
The SAI upgrade introduces a two-piece Y-shaped piston seal for lower start-up pressure and extended life. Note that a standard cylinder drifts without live air; for load holding, consider the SAIL or BSAI lock variants, or an external pilot check valve.
Airtac SI125 Standard Cylinder SI125BX250 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX250 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX250 |
| Bore size | Ø125 mm |
| Stroke | 250 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 SAI125BX250 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 SAI125BX250 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 SI125BX250
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×250 | 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 SI125BX250 Is Used
Heavy Press Operations
Drives substantial forming and stamping presses requiring up to 6136 N of thrust at 0.5 MPa, utilizing the robust 32 mm SUS304 rod.
Material Extrusion
Actuates large clamping doors or heavy material guides in extrusion lines, benefiting from the 40 mm adjustable end cushions.
Replacing the Airtac SI125 Standard Cylinder SI125BX250 with the SAI125BX250
To replace the discontinued SI125BX250, order the SAI125BX250. Verify your existing fixture matches the ISO 15552 mounting dimensions, and confirm the G1/2 port, M27x2 rod thread, and 250 mm stroke. Because this specific SKU has no magnet (-S), it cannot support legacy CS1-B/DS1-B sensors; if position detection is required, switch to an SAI125X250S model and current AirTAC switches. Operating speed is 30-500 mm/s. If downsizing, a 100 mm bore offers 3927 N push at 0.5 MPa; if upsizing, a 160 mm bore yields 10053 N. For load holding on air loss, specify the SAIL air-released lock or BSAI clamp-lock variant, as the standard air cushion only decelerates near stroke end.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX250
- ✓ 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 SI125BX250 FAQ
Yes, the AirTAC SI125BX250 is discontinued. The direct replacement is the SAI125BX250. It is dimensionally interchangeable per ISO 15552, keeping the same 125 mm bore, 250 mm stroke, G1/2 port, and mounting interface.
This double-acting cylinder uses a G1/2 air port. At 0.5 MPa it provides 6136 N push and 5734 pull force. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX250
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX250 replacement — usually within 7-8 hours.