This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X450S, 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 SI125X450S
The AirTAC SI125 Standard Cylinder SI125X450S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 450mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X450S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke450 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X450S
- 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 SI125X450S
The AirTAC SI125X450S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 450 mm stroke. Delivering 6136 N push force at 0.5 MPa via a G1/2 port, its direct replacement is the SAI125X450S, retaining identical mounting, stroke, and output. The SAI upgrade features a new piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life.
This legacy SI unit includes a piston magnet for CS1-B/DS1-B switches, while the SAI successor uses current AirTAC sensors. The original line lacked integrated lock options, but the SAI family adds SAIL (air-released lock) and BSAI (clamp-lock) variants. Note that a standard cylinder drifts without live air; the 40 mm cushions only decelerate near stroke ends. For high-temperature needs, Viton H seals raise the operating range to 150 C.
Airtac SI125 Standard Cylinder SI125X450S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X450S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X450S |
| Bore size | Ø125 mm |
| Stroke | 450 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 SAI125X450S 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 SAI125X450S 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 SI125X450S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×450 | 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 SI125X450S Is Used
Heavy Pressing
Applies the 6136 N push force at 0.5 MPa for seating bearings and forming heavy components in automated machinery.
Pallet Diverting
Handles large 450 mm strokes to push heavy pallets off high-throughput packaging and warehouse conveyor lines.
Replacing the Airtac SI125 Standard Cylinder SI125X450S with the SAI125X450S
To replace the discontinued SI125X450S, order the SAI125X450S. It is a direct per ISO 15552 mounting-interface dimensions, matching the 125 mm bore, 450 mm stroke, G1/2 port, and M27x2 rod thread. Confirm your mounting accessory (LB, FA, TC, etc.) and retain the -S magnet for position sensing. When sizing both ways, the neighboring 100 mm bore yields 3927 N push at 0.5 MPa, while the 160 mm bore yields 10053 N. The 125 mm bore delivers 6136 N push and 5734 N pull at 0.5 MPa, with a max theoretical force of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s. Because the stroke is 450 mm, use an external guide to prevent rod bending and side-load wear. A plain cylinder does not hold load on air loss; for load holding, use the SAIL or BSAI lock variant, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X450S
- ✓ 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 SI125X450S FAQ
Yes, the AirTAC SI125X450S is discontinued. The direct replacement is the SAI125X450S. It is dimensionally interchangeable per ISO 15552 mounting-interface dimensions, retaining the same 125 mm bore, 450 mm stroke, output force, G1/2 port, and mounting accessories.
The 125 mm bore uses a G1/2 port and M27x2 rod thread. 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 maximum of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X450S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X450S replacement — usually within 7-8 hours.