This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X390S, 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 SI125X390S
The AirTAC SI125 Standard Cylinder SI125X390S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 390mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X390S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke390 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X390S
- 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 SI125X390S
The AirTAC SI125X390S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 390 mm stroke. Providing 6136 N push force at 0.5 MPa, it features a G1/2 port, M27x2 rod thread, and a piston magnet for CS1-B/DS1-B sensors. The direct replacement is the SAI125X390S.
The SAI upgrade retains identical ISO 15552 mounting dimensions, force, and stroke, but uses an upgraded two Y-shaped one-way piston seal for low start-up pressure. The SAI family also adds SAIL and BSAI lock variants absent in the SI line.
Airtac SI125 Standard Cylinder SI125X390S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X390S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X390S |
| Bore size | Ø125 mm |
| Stroke | 390 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 SAI125X390S 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 SAI125X390S 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 SI125X390S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×390 | 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 SI125X390S Is Used
Heavy Press Clamping
Secures large metal castings during machining, utilizing the 6136 N push force to hold components firmly against the fixture.
Pallet Lift Stations
Drives vertical lifting arms for heavy loaded pallets, where the 390 mm stroke provides the necessary elevation reach.
Bulk Material Diversion
Actuates heavy-duty routing gates on high-capacity conveyor lines, relying on adjustable 40 mm cushions to decelerate the load.
Replacing the Airtac SI125 Standard Cylinder SI125X390S with the SAI125X390S
To replace the SI125X390S, order the SAI125X390S. Confirm the ISO 15552 interface, 125 mm bore, 390 mm stroke, G1/2 port (PT/G/NPT), and mounting accessory. The -S suffix means a magnet for legacy CS1-B/DS1-B sensors; the SAI uses current AirTAC switches. Neighbouring bores: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. Note that a plain cylinder drifts without live air; for load holding, use an external pilot check valve or the SAIL/BSAI lock variant. Because the 390 mm stroke is long, use an external guide to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X390S
- ✓ 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 SI125X390S FAQ
Yes, the AirTAC SI125X390S is discontinued. The direct replacement is the SAI125X390S. It is dimensionally interchangeable per ISO 15552, offering the same 125 mm bore, 390 mm stroke, 6136 N force, G1/2 port, and mounting interface.
At 0.5 MPa, the push force is 6136 N and pull is 5734 N. At 0.7 MPa push is 8590 N, and at 0.9 MPa it is 11045 N. The theoretical max force is 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X390S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X390S replacement — usually within 7-8 hours.