This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X345S, 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 SI125X345S
The AirTAC SI125 Standard Cylinder SI125X345S 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 SAI125X345S, 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 → SAI125X345S
- 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 SI125X345S
The AirTAC SI125X345S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 345 mm stroke. Delivering 6136 N push force at 0.5 MPa via a G1/2 port, it is directly replaced by the SAI125X345S. This direct upgrade matches the original ISO 15552 mounting interface, bore, stroke, output force, and accessories, fitting existing fixtures perfectly.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also introduces SAIL, SAIF, and BSAI lock variants absent from the SI line. Your -S suffix indicates a piston magnet for legacy CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125X345S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X345S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X345S |
| 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 SAI125X345S 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 SAI125X345S 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 SI125X345S
| 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 SI125X345S Is Used
Heavy Stamping Press
Drives heavy tooling in stamping presses, utilizing the 6136 N push force at 0.5 MPa to form thick metal components reliably.
Pallet Transfer Unit
Shifts loaded pallets across conveyor junctions, where the 313 kg vertical lift capacity and 345 mm stroke handle substantial material routing.
Large Mold Actuation
Opens and closes large injection molds, relying on the 125 mm bore's 11045 N output at 0.9 MPa for high-force clamping operations.
Replacing the Airtac SI125 Standard Cylinder SI125X345S with the SAI125X345S
To replace the SI125X345S, order the SAI125X345S, confirming the ISO 15552 interface, 125 mm bore, 345 mm stroke, G1/2 port, and mounting accessory. The -S magnet equips legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, whereas a 160 mm bore yields 10053 N. A plain cylinder drifts on air loss since cushions only decelerate; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI variants. Because the 345 mm stroke is long, use external guides to prevent rod bending and side-load wear. Rod material options include carbon steel, SUS420J2 (A), and SUS304 (B).
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X345S
- ✓ 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 SI125X345S FAQ
Yes, the SI125X345S is discontinued. The direct replacement is the SAI125X345S. It is dimensionally interchangeable per the ISO 15552 mounting interface, retaining the same 125 mm bore, 345 mm stroke, force, G1/2 port, and mounting fixtures.
The 125 mm bore features a G1/2 port. It delivers 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 force of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X345S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X345S replacement — usually within 7-8 hours.