This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X350STC, 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 SI125X350STC
The AirTAC SI125 Standard Cylinder SI125X350STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 350mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X350STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke350 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X350STC
- 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 SI125X350STC
The AirTAC SI125X350STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 350 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. AirTAC replaced this legacy unit with the SAI125X350STC, a direct upgrade sharing the exact ISO 15552 mounting interface, TC trunnion mount, stroke and output force.
The SAI upgrade features a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also introduces SAIL and BSAI lock variants absent in the SI line. Your -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X350STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X350STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X350STC |
| Bore size | Ø125 mm |
| Stroke | 350 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 SAI125X350STC 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 SAI125X350STC 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 SI125X350STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×350 | 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 SI125X350STC Is Used
Heavy Pressing
Applies 8590 N of thrust at 0.7 MPa for seating heavy components and forming operations on automated lines.
Pallet Diversion
Uses the 350 mm stroke to push large pallets sideways onto spur lanes without requiring external extensions.
Replacing the Airtac SI125 Standard Cylinder SI125X350STC with the SAI125X350STC
To replace the SI125X350STC, order the SAI125X350STC. It drops directly into existing fixtures via the ISO 15552 TC trunnion interface, keeping the 125 mm bore, 350 mm stroke, G1/2 port and M27x2 rod thread. When sizing both ways, neighbouring bores offer different force classes, but this 125 mm bore yields a theoretical maximum of 1251 kgf at 1.0 MPa. Because the 350 mm stroke is long, use an external guide to prevent rod bending and side-load damage. A plain cylinder drifts on air loss; the 40 mm adjustable air cushion only decelerates near stroke end. For load holding, specify an external pilot check valve, or choose the SAIL or BSAI lock variant. Rod material options include carbon steel, SUS420J2 (A) or SUS304 (B).
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X350STC
- ✓ 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 SI125X350STC FAQ
Yes, the SI125X350STC is discontinued. The direct replacement is the SAI125X350STC. It shares the identical ISO 15552 mounting interface, 125 mm bore, 350 mm stroke, G1/2 port and output force, fitting existing fixtures perfectly.
The bore is 125 mm with a G1/2 port. Force ratings 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 max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X350STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X350STC replacement — usually within 7-8 hours.