This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400S, 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 SI125X400S
The AirTAC SI125 Standard Cylinder SI125X400S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X400S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X400S
- 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 SI125X400S
The AirTAC SI125X400S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 400 mm stroke. Delivering 6136 N push force at 0.5 MPa, it features a G1/2 port, M27x2 rod thread, and a built-in piston magnet for legacy CS1-B/DS1-B sensors. AirTAC replaced this EOL unit with the SAI125X400S.
The SAI125X400S is a direct replacement matching the ISO 15552 mounting interface, bore, stroke, force, and port. It upgrades the piston seal to two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125X400S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400S |
| Bore size | Ø125 mm |
| Stroke | 400 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 SAI125X400S 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 SAI125X400S 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 SI125X400S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×400 | 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 SI125X400S Is Used
Heavy Press Operations
Drives 125 mm bore actuators for high-tonnage pressing and forming tasks requiring up to 11045 N of thrust at 0.9 MPa.
Pallet Transfer
Shifts heavy loaded pallets over 400 mm strokes, benefiting from external guides to prevent rod bending under mass.
Large Mold Handling
Positions industrial molds and heavy tooling, using the G1/2 port and 32 mm rod to manage substantial inertial loads.
Replacing the Airtac SI125 Standard Cylinder SI125X400S with the SAI125X400S
To replace the SI125X400S, order the SAI125X400S. Confirm the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/2 port, and the magnet (-S). The SAI accepts current AirTAC switches where the SI used CS1-B/DS1-B. Sizing both ways: a 100 mm bore yields 3927 N [email protected], while a 160 mm bore yields 10053 N. At 400 mm stroke, prevent rod bending by using an external guide to absorb side loads. A plain cylinder drifts on air loss—the cushion only decelerates. For load holding, specify the SAIL or BSAI lock variant, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400S
- ✓ 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 SI125X400S FAQ
Yes, the SI125X400S is discontinued. The direct replacement is the SAI125X400S. It matches the ISO 15552 mounting interface, 125 mm bore, 400 mm stroke, output force, and G1/2 port, fitting existing fixtures directly.
It has a G1/2 port. 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. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400S replacement — usually within 7-8 hours.