This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X345STC, 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 SI125X345STC
The AirTAC SI125 Standard Cylinder SI125X345STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 345mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X345STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke345 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X345STC
- 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 SI125X345STC
The AirTAC SI125X345STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 345 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. AirTAC replaced this legacy unit with the SAI125X345STC, a direct sharing the exact TC trunnion mount, M27x2 thread, and dimensions.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. It adds SAIL and BSAI lock variants absent in the SI line. Your -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125X345STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X345STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X345STC |
| Bore size | Ø125 mm |
| Stroke | 345 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 SAI125X345STC 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 SAI125X345STC 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 SI125X345STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×345 | 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 SI125X345STC Is Used
Heavy Stamping Press
Drives large dies and heavy platens in metal forming, utilizing the 6136 N push force to shape thick steel blanks reliably.
Pallet Dispenser
Indexes empty pallets into high-throughput packaging lines, using the 345 mm stroke and TC trunnion mount to handle heavy loads.
Automated Assembly Fixture
Actuates large clamping mechanisms holding bulky machinery components in place during precision fastening operations.
Replacing the Airtac SI125 Standard Cylinder SI125X345STC with the SAI125X345STC
To replace the SI125X345STC, order the SAI125X345STC. Verify the ISO 15552 TC trunnion interface, 125 mm bore, 345 mm stroke, G1/2 port, and -S magnet for CS1-B/DS1-B switches. The SAI family adds SAIL air-released lock and BSAI clamp-lock variants if you need load holding, as a plain cylinder drifts without air and its cushion only decelerates. For 345 mm strokes, use external guides to prevent rod bending and side-load wear. If downsizing, a 100 mm bore gives 3927 N at 0.5 MPa; if upsizing, a 160 mm bore yields 10053 N. Rod materials include carbon steel, SUS420J2, or SUS304.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X345STC
- ✓ 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 SI125X345STC FAQ
Yes, the AirTAC SI125X345STC is discontinued. The direct replacement is the SAI125X345STC. It shares the identical ISO 15552 mounting interface, 125 mm bore, 345 mm stroke, G1/2 port, and TC mount, fitting existing fixtures perfectly.
This double-acting cylinder uses a G1/2 port. At 0.5 MPa it provides 6136 N push and 5734 N pull force. At 0.7 MPa push is 8590 N, and at 0.9 MPa it is 11045 N. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X345STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X345STC replacement — usually within 7-8 hours.