This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX425, 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 SI125BX425
The AirTAC SI125 Standard Cylinder SI125BX425 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 425mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX425, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke425 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX425
- 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 SI125BX425
The AirTAC SI125BX425 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore and 425 mm stroke. It delivers 6136 N push force at 0.5 MPa and uses a G1/2 air port. The direct replacement is the SAI125BX425, which shares the exact ISO 15552 mounting interface, bore, stroke, output force, and port size. This SKU includes a SUS304 stainless steel piston rod for corrosion resistance, but lacks a magnet and cannot support sensing switches.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. Note that this plain cylinder does not hold load on air loss; the cushion only decelerates. For held loads, consider the SAIL or BSAI lock variants.
Airtac SI125 Standard Cylinder SI125BX425 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX425 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX425 |
| Bore size | Ø125 mm |
| Stroke | 425 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 SAI125BX425 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 SAI125BX425 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 SI125BX425
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×425 | 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 SI125BX425 Is Used
Heavy Press Clamping
Secures large metal or composite panels during machining, utilizing the 6136 N push force and 425 mm reach to accommodate thick workpieces.
Bulk Material Diversion
Drives large-scale sorting flaps on high-capacity packaging lines, moving heavy cartons with a 5734 N pull force at 0.5 MPa.
Replacing the Airtac SI125 Standard Cylinder SI125BX425 with the SAI125BX425
To replace the discontinued SI125BX425, order the SAI125BX425. Confirm the ISO 15552 mounting interface (LB, FA, CA, TC, etc.), the 425 mm stroke, and the G1/2 port. Because this SKU lacks the -S magnet, it cannot accept CS1-B/DS1-B sensors; if position detection is needed, order an SAI125BX425S instead. Sizing both ways: a 100 mm bore gives 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. At 425 mm stroke, prevent rod bending by guiding the load externally to avoid side loads. For load holding on air loss, use an external pilot check valve or the SAIL/BSAI lock variants, as the cushion only decelerates.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX425
- ✓ 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 SI125BX425 FAQ
Yes, the AirTAC SI125BX425 is discontinued. The direct replacement is the SAI125BX425. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 425 mm stroke, 6136 N push force at 0.5 MPa, and G1/2 port, so it drops directly into existing fixtures.
This double-acting cylinder features a G1/2 air port. The 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. It operates at 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX425
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX425 replacement — usually within 7-8 hours.