This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX550SH, 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 SI125BX550SH
The AirTAC SI125 Standard Cylinder SI125BX550SH is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 550mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX550SH, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke550 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX550SH
- 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 SI125BX550SH
The AirTAC SI125BX550SH is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 550 mm stroke, SUS304 stainless rod, high-temp Viton H seals, and a piston magnet. Delivering 6136 N push force at 0.5 MPa, it is replaced by the direct replacement SAI125BX550SH. This SAI model shares the exact G1/2 port, M27x2 thread, and ISO 15552 mounting interface, fitting existing fixtures seamlessly.
The SAI upgrade features an advanced two Y-shaped one-way piston seal for low start-up pressure and long life. Note that standard cylinders drift without live air; for load holding, explore the SAIL or BSAI lock variants, or use an external pilot check valve.
Airtac SI125 Standard Cylinder SI125BX550SH Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX550SH |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX550SH |
| Bore size | Ø125 mm |
| Stroke | 550 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 SAI125BX550SH 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 SAI125BX550SH 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 SI125BX550SH
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×550 | 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 SI125BX550SH Is Used
High-Temp Material Forming
Drives heavy press doors or mold halves in ambient heat up to 150 C, utilizing the Viton H seal and SUS304 rod to resist thermal degradation and corrosion.
Large Pallet Diversion
Actuates heavy-duty routing gates on 125 mm bore conveyors, moving substantial loads with a safe working capacity near 3682 N at 0.5 MPa.
Vertical Lift Stations
Hoists 313 kg platforms in automated storage systems using the 550 mm stroke, requiring external guides to manage rod side-load over long extensions.
Replacing the Airtac SI125 Standard Cylinder SI125BX550SH with the SAI125BX550SH
To replace the discontinued SI125BX550SH, order the SAI125BX550SH. It is a direct upgrade: matching the 125 mm bore, 550 mm stroke, G1/2 port, M27x2 rod thread, and ISO 15552 mounting dimensions. Keep the -B (SUS304 rod) for corrosion resistance and -H (Viton H) for high-temperature 0-150 C environments. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family uses current AirTAC switches. If sizing alternatives, neighboring bores or the 8590 N push force at 0.7 MPa provide scaling options. Because 550 mm exceeds 300 mm, add external guides to prevent rod bending and side-load damage. For load holding on air loss, specify the SAIL or BSAI lock variant, or an external rod lock.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX550SH
- ✓ 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 SI125BX550SH FAQ
Yes, the SI125BX550SH is discontinued. The direct replacement is the SAI125BX550SH. It shares the same ISO 15552 mounting interface, 125 mm bore, 550 mm stroke, output force, and G1/2 port, fitting directly into your existing fixtures.
It 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. The rod is SUS304 stainless with an M27x2 thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX550SH
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX550SH replacement — usually within 7-8 hours.