This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX55, 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 SI125BX55
The AirTAC Airtac SI125 Standard Cylinder SI125BX55 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 55mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX55, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke55 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX55
- 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 SI125BX55
The AirTAC SI125BX55 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 55 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125BX55, matching the interface, force, and stroke. This specific SKU uses a SUS304 stainless steel rod (-B) for corrosion resistance, but lacks a magnet (-S), meaning it cannot accept position sensors.
The SAI125BX55 upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. For load holding, note that standard cylinders drift without live air; the cushion only decelerates. Use an external pilot check valve or the SAIL/BSAI lock variants.
Airtac SI125 Standard Cylinder SI125BX55 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX55 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX55 |
| Bore size | Ø125 mm |
| Stroke | 55 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 SAI125BX55 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 SAI125BX55 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 SI125BX55
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×55 | 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 SI125BX55 Is Used
Heavy Press Clamping
Generates 6136 N of push force at 0.5 MPa to secure large metal castings during machining operations.
Pallet Positioning Stops
The SUS304 stainless rod resists moisture in logistics hubs while halting heavy 313 kg vertical loads.
Mold Ejection Systems
Short 55 mm stroke provides rapid, high-force ejection of industrial rubber molds without live air drift.
Replacing the Airtac SI125 Standard Cylinder SI125BX55 with the SAI125BX55
To replace the SI125BX55, order the SAI125BX55. Verify the ISO 15552 mounting interface, the 55 mm stroke, the G1/2 port, and your mounting accessories. Because this SKU lacks a magnet, it cannot support legacy CS1-B/DS1-B sensors; if sensing is needed, order an SAI with the S suffix. This -B variant provides a SUS304 stainless rod instead of carbon steel. For sizing, a 100 mm bore offers 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. Operating speed is 30-500 mm/s. For any load holding, add an external rod lock, as the air cushion only decelerates and does not brake.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX55
- ✓ 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 SI125BX55 FAQ
Yes, the SI125BX55 is discontinued. The direct replacement is the AirTAC SAI125BX55. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 55 mm stroke, G1/2 port, and mounting interface.
It features a G1/2 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX55
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX55 replacement — usually within 7-8 hours.