This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X300SFA, 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 SI125X300SFA
The AirTAC SI125 Standard Cylinder SI125X300SFA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 300mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X300SFA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke300 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X300SFA
- 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 SI125X300SFA
The AirTAC SI125X300SFA is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 300 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125X300SFA, which matches the exact interface, bore, stroke, force, port and FA flange mounting.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. It also adds variants the SI lacked, like the SAIL lock and BSAI clamp-lock. The -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125X300SFA Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X300SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X300SFA |
| Bore size | Ø125 mm |
| Stroke | 300 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 SAI125X300SFA 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 SAI125X300SFA 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 SI125X300SFA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×300 | 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 SI125X300SFA Is Used
Heavy Stamping Press
Drives large platens and stamping dies requiring high thrust, using the 6136 N push force at 0.5 MPa to form thick metal components reliably.
Pallet Positioning
Shifts loaded pallets along roller conveyors, utilizing the 313 kg vertical lift capacity and FA flange mount for rigid heavy-frame integration.
Large Mold Clamping
Secures heavy industrial molds during processing, relying on the 125 mm bore and adjustable 40 mm air cushions to absorb end-of-stroke impact.
Replacing the Airtac SI125 Standard Cylinder SI125X300SFA with the SAI125X300SFA
To replace the SI125X300SFA, order the SAI125X300SFA. Verify the ISO 15552 interface, 125 mm bore, 300 mm stroke, G1/2 port, FA flange mount, and -S magnet. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. At 0.7 MPa this 125 mm unit pushes 8590 N. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. With a 300 mm stroke, use external guides to prevent rod bending and side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X300SFA
- ✓ 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 SI125X300SFA FAQ
Yes, the SI125X300SFA is discontinued. The direct replacement is the SAI125X300SFA. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 300 mm stroke, G1/2 port, FA flange mounting, and output force.
It features a G1/2 air port and M27x2 rod thread. Force output is 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 of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X300SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X300SFA replacement — usually within 7-8 hours.