This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400, 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 SI125X400
The AirTAC SI125 Standard Cylinder SI125X400 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 SAI125X400, 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 → SAI125X400
- 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 SI125X400
The AirTAC SI125X400 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 400 mm stroke. It delivers 6136 N push force at 0.5 MPa and uses a G1/2 port. AirTAC replaced this legacy unit with the SAI125X400, a direct upgrade sharing the exact ISO 15552 mounting interface, bore, stroke, output force, and accessories.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note this specific SKU lacks a magnet, so it cannot accept position sensors like the legacy CS1-B/DS1-B switches.
Airtac SI125 Standard Cylinder SI125X400 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400 |
| 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 SAI125X400 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 SAI125X400 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 SI125X400
| 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 SI125X400 Is Used
Heavy Stamping Press
Drives large platens in metal forming, using the 6136 N push force to shape thick gauge materials reliably.
Automated Clamping Cell
Secures heavy machinery frames during machining operations, utilizing the 400 mm stroke to clear large workpieces.
Replacing the Airtac SI125 Standard Cylinder SI125X400 with the SAI125X400
To replace the SI125X400, order the SAI125X400. Confirm the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/2 port thread (PT, G, or NPT), and the 400 mm stroke. Because this SKU has no magnet (-S), it cannot support sensing; if switches are needed, specify an SAI125X400S. Sizing both ways: a 125 mm bore yields 6136 N push at 0.5 MPa, while the neighboring 100 mm bore offers 3927 N. For load holding on air loss, note that standard cylinders drift; use an external pilot check valve or the SAIL/BSAI lock variants. Finally, for this 400 mm stroke, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400
- ✓ 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 SI125X400 FAQ
Yes, the AirTAC SI125X400 is discontinued. The direct replacement is the SAI125X400. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 400 mm stroke, G1/2 port, and mounting interface to fit existing fixtures directly.
At 0.5 MPa it provides 6136 N push and 5734 pull force. Push force is 8590 N at 0.7 MPa, 11045 N at 0.9 MPa, and the theoretical max is 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s. The G1/2 port and 40 mm adjustable cushions manage deceleration.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X400
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400 replacement — usually within 7-8 hours.