This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X250SN, 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 SI125X250SN
The AirTAC SI125 Standard Cylinder SI125X250SN 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 SAI125X250SN, 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 → SAI125X250SN
- 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 SI125X250SN
The AirTAC SI125X250SN is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 250 mm stroke. It delivers 6136 N push force at 0.5 MPa through a G1/2 port. The direct replacement is the SAI125X250SN, matching the exact bore, stroke, force, port, and mounting interface.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. It also adds SAIL, SAIF, and BSAI variants the SI lacked. The NBR seal handles -20 to +70 C, while Viton H extends this.
Airtac SI125 Standard Cylinder SI125X250SN Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X250SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X250SN |
| 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 SAI125X250SN 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 SAI125X250SN 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 SI125X250SN
| 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 SI125X250SN Is Used
Heavy Pressing
Drives large stamping or forming presses requiring 6136 N of push force at 0.5 MPa.
Pallet Handling
Indexes heavy loaded pallets on conveyors, utilizing the 313 kg vertical lift capacity.
Mold Clamping
Secures industrial molds and heavy tooling fixtures firmly during manufacturing operations.
Replacing the Airtac SI125 Standard Cylinder SI125X250SN with the SAI125X250SN
To replace the SI125X250SN, order the SAI125X250SN. Verify the ISO 15552 mounting interface, 125 mm bore, 250 mm stroke, G1/2 port, and your specific mounting accessory. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. The -N NBR seal is standard. For sizing, the 100 mm bore offers 3927 N push at 0.5 MPa, and the 160 mm bore offers 10053 N. A plain cylinder drifts without live air; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 250 mm stroke, guide rods prevent side-load rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X250SN
- ✓ 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 SI125X250SN FAQ
Yes, the SI125X250SN is discontinued. The direct replacement is the SAI125X250SN. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 250 mm stroke, output force, G1/2 port, and mounting interface.
This double-acting cylinder features a G1/2 port. It delivers 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical max force of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X250SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X250SN replacement — usually within 7-8 hours.