This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X445S, 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 SI125X445S
The AirTAC SI125 Standard Cylinder SI125X445S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 445mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X445S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke445 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X445S
- 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 SI125X445S
The AirTAC SI125X445S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 445mm stroke. Delivering 6136 N push force at 0.5 MPa through a G1/2 port, it is replaced by the SAI125X445S. This direct upgrade matches the original bore, stroke, force, and mounting interface exactly.
The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. It also introduces SAIL, SAIF, and BSAI variants the SI lacked. The -S magnet supports CS1-B/DS1-B sensors, while Viton H seals raise heat resistance to 150 C.
Airtac SI125 Standard Cylinder SI125X445S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X445S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X445S |
| Bore size | Ø125 mm |
| Stroke | 445 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 SAI125X445S 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 SAI125X445S 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 SI125X445S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×445 | 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 SI125X445S Is Used
Heavy Stamping Press
Drives large heavy-duty stamping dies requiring 6136 N push force at 0.5 MPa with robust 125mm bore stability.
Automated Assembly Fixture
Actuates large industrial clamps on machining lines, utilizing the adjustable 40mm air cushions to decelerate heavy loads.
Replacing the Airtac SI125 Standard Cylinder SI125X445S with the SAI125X445S
To replace the SI125X445S, order the SAI125X445S direct. Confirm the ISO 15552 mounting interface, 125mm bore, 445mm stroke, G1/2 port (PT/G/NPT), and mounting accessory. The -S magnet enables CS1-B/DS1-B sensors, though the SAI uses current AirTAC switches. For sizing, neighboring bores offer different forces: 100mm yields 3927 N [email protected], while 160mm yields 10053 N. At 445mm stroke, use external guides to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X445S
- ✓ 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 SI125X445S FAQ
Yes, the SI125X445S is discontinued. The direct replacement is the AirTAC SAI125X445S. It is dimensionally interchangeable per ISO 15552, matching the 125mm bore, 445mm stroke, 6136 N force, G1/2 port, and mounting fixtures.
The bore is 125mm with a G1/2 air 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. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X445S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X445S replacement — usually within 7-8 hours.