This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400LB, 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 SI125X400LB
The AirTAC SI125 Standard Cylinder SI125X400LB is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X400LB, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X400LB
- 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 SI125X400LB
The AirTAC SI125X400LB is a discontinued double-acting ISO 15552 profile cylinder with an LB foot mount. Built for heavy loads, it delivers 6136 N push and 5734 N pull at 0.5 MPa through a G1/2 port. Because this legacy unit is end-of-life, you should order the direct replacement: the SAI125X400LB. It shares the same ISO 15552 mounting interface, 125 mm bore, 400 mm stroke, force, and port, dropping straight into existing LB foot fixtures.
The SAI upgrade introduces a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note this specific SKU lacks a magnet, so it cannot accept CS1-B or DS1-B sensors. If you need load holding on air loss, explore the SAIL or BSAI lock variants, as standard cushions only decelerate.
Airtac SI125 Standard Cylinder SI125X400LB Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400LB |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400LB |
| Bore size | Ø125 mm |
| Stroke | 400 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 SAI125X400LB 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 SAI125X400LB 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 SI125X400LB
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×400 | 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 SI125X400LB Is Used
Heavy Press Actuation
Drives large pressing and stamping operations requiring up to 11045 N of thrust at 0.9 MPa.
Pallet Diversion
Shifts heavy pallets along high-capacity material handling lines using the robust LB foot mount.
Replacing the Airtac SI125 Standard Cylinder SI125X400LB with the SAI125X400LB
To replace the discontinued SI125X400LB, order the SAI125X400LB. Confirm the ISO 15552 LB foot mounting matches your fixture, alongside the 125 mm bore, 400 mm stroke, and G1/2 port (available in PT, G, or NPT). This SKU has no magnet (-S), meaning it cannot support position sensing; if you require switches, select an SAI125X400LBS and use current AirTAC sensors. For sizing alternatives, a neighboring 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore provides 10053 N. Keep in mind a standard cylinder drifts without live air—the cushion only decelerates—so use an external rod lock or pilot check valve for holding. Finally, the 400 mm stroke demands external guides to prevent rod bending and manage side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400LB
- ✓ 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 SI125X400LB FAQ
Yes, the SI125X400LB is discontinued. The direct replacement is the SAI125X400LB. It is a true ISO 15552 profile cylinder that matches the 125 mm bore, 400 mm stroke, output force, G1/2 port, and LB foot mounting interface.
At 0.5 MPa it provides 6136 N push and 5734 N pull. 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 SAI125X400LB
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400LB replacement — usually within 7-8 hours.