This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X402SN, 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 SI125X402SN
The AirTAC SI125 Standard Cylinder SI125X402SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 402mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X402SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke402 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X402SN
- 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 SI125X402SN
The AirTAC SI125X402SN is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 402 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125X402SN, matching the bore, stroke, G1/2 port, M27x2 rod thread and ISO 15552 mounting interface. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
This legacy SI unit includes a piston magnet for CS1-B/DS1-B switches and an NBR seal rated for -20 to +70 C. The SAI family introduces variants the SI lacked, such as the SAIL air-released lock and BSAI clamp-lock for load holding. Note that a plain cylinder drifts on air loss; the adjustable 40 mm cushions only decelerate near stroke ends. For high-temperature needs up to 150 C, specify the Viton H seal option.
Airtac SI125 Standard Cylinder SI125X402SN Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X402SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X402SN |
| Bore size | Ø125 mm |
| Stroke | 402 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 SAI125X402SN 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 SAI125X402SN 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 SI125X402SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×402 | 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 SI125X402SN Is Used
Heavy Press Clamping
Provides 6136 N of thrust at 0.5 MPa to secure large metal castings or heavy composite molds during machining and pressing operations.
Bulk Product Diverters
Drives high-inertia diverters on packaging lines, relying on the 40 mm adjustable air cushions to decelerate the 402 mm stroke smoothly.
Replacing the Airtac SI125 Standard Cylinder SI125X402SN with the SAI125X402SN
To replace the SI125X402SN, order the SAI125X402SN. Confirm the ISO 15552 mounting interface (LB, FA, CA, TC, etc.), the G1/2 port, the M27x2 rod thread, the -S magnet for current AirTAC switches, and the -N NBR seal. Operating pressure is 0.15-1.0 MPa. Sizing both ways: the neighbouring 100 mm bore gives 3927 N push at 0.5 MPa, while the 160 mm bore yields 10053 N. Because this is a 402 mm stroke, prevent rod bending by using an external guide to absorb side loads. A standard cylinder does not hold load without live air; for fail-safe holding, use an external pilot check valve or the SAIL/BSAI lock variants. Speed is 30-500 mm/s.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X402SN
- ✓ 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 SI125X402SN FAQ
Yes, the SI125X402SN is discontinued. The direct replacement is the SAI125X402SN. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 402 mm stroke, G1/2 port, M27x2 thread, and mounting interface.
It has a G1/2 port. The thrust figures are: 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 maximum of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X402SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X402SN replacement — usually within 7-8 hours.