This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400N, 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 SI125X400N
The AirTAC SI125 Standard Cylinder SI125X400N 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 SAI125X400N, 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 → SAI125X400N
- 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 SI125X400N
The AirTAC SI125X400N 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. The direct replacement is the SAI125X400N, which maintains the exact same interface, port, and force.
This NBR-sealed unit has no magnet and cannot accept a sensor. The SAI upgrade features a two-piece Y-shaped piston seal for lower start-up pressure. For load holding, note the cushion only decelerates; use a pilot check valve or SAIL lock variant.
Airtac SI125 Standard Cylinder SI125X400N Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400N |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400N |
| 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 SAI125X400N 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 SAI125X400N 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 SI125X400N
| 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 SI125X400N Is Used
Heavy Pressing
Drives large stamping or forming fixtures requiring substantial push force over a 400 mm travel distance.
Pallet Handling
Actuates heavy load diverter arms or lift stations in automated conveyor lines using G1/2 ports.
Mold Clamping
Secures large industrial molds or heavy tooling bases where a robust 125 mm bore is necessary.
Replacing the Airtac SI125 Standard Cylinder SI125X400N with the SAI125X400N
To replace the SI125X400N, order the SAI125X400N. Verify the ISO 15552 mounting interface, 400 mm stroke, G1/2 port, and M27x2 rod thread. This non-magnetic SKU lacks a sensor groove switch. If sizing up or down, compare neighbouring bores and the 0.5 MPa ratings. Because the 400 mm stroke is long, use external guides to prevent rod bending and side loads. For holding loads without air, select the SAIL or BSAI lock variant, as standard cushions only decelerate.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400N
- ✓ 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 SI125X400N FAQ
Yes, the SI125X400N is discontinued. The direct replacement is the SAI125X400N. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 400 mm stroke, G1/2 port, and mounting interface.
The G1/2 port bore delivers 6136 N push and 5734 N pull at 0.5 MPa. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical max force is 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X400N
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400N replacement — usually within 7-8 hours.