This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX70S, 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 SI125BX70S
The AirTAC SI125 Standard Cylinder SI125BX70S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 70mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX70S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke70 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX70S
- 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 SI125BX70S
The AirTAC SI125BX70S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore, 70 mm stroke, and a SUS304 stainless steel piston rod. It delivers 6136 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125BX70S, a direct replacement retaining the exact ISO 15552 mounting interface, G1/2 port, and output force. The SAI upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life.
This specific B-variant rod resists corrosion, and the built-in magnet supports legacy CS1-B/DS1-B sensors. Note that a plain cylinder drifts without live air; for load holding, explore the SAIL or BSAI lock variants.
Airtac SI125 Standard Cylinder SI125BX70S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX70S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX70S |
| Bore size | Ø125 mm |
| Stroke | 70 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 SAI125BX70S 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 SAI125BX70S 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 SI125BX70S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×70 | 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 SI125BX70S Is Used
Heavy Press Clamping
Applies the 6136 N push force at 0.5 MPa to secure heavy steel plates during machining or welding operations.
Corrosive Washdowns
The SUS304 stainless rod excels in food or chemical washdown environments where standard carbon steel rods fail.
Replacing the Airtac SI125 Standard Cylinder SI125BX70S with the SAI125BX70S
To replace the SI125BX70S, order the SAI125BX70S. Confirm the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/2 port thread (PT/G/NPT), and the -S magnet for current AirTAC switches. Sizing both ways: a neighbouring 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. If your application needs positive load holding on air loss, a plain cylinder cannot lock—the cushion only decelerates. Specify an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX70S
- ✓ 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 SI125BX70S FAQ
Yes, the AirTAC SI125BX70S is discontinued. The direct replacement is the SAI125BX70S. It shares the identical ISO 15552 mounting interface, 125 mm bore, 70 mm stroke, and G1/2 port, fitting existing fixtures perfectly.
The 125 mm bore uses a G1/2 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 is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX70S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX70S replacement — usually within 7-8 hours.