This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX50, 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 SI125BX50
The AirTAC SI125 Standard Cylinder SI125BX50 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 50mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX50, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke50 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX50
- 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 SI125BX50
The AirTAC SI125BX50 is a discontinued double-acting ISO 15552 profile cylinder featuring a SUS304 stainless piston rod. It delivers 6136 N push force at 0.5 MPa through a G1/2 port. AirTAC replaced this legacy unit with the SAI125BX50, a direct sharing the exact bore, stroke, and mounting interface.
The SAI upgrade features two Y-shaped piston seals for low start-up pressure and long life. Note this SKU lacks a magnet, so it cannot accept position switches.
Airtac SI125 Standard Cylinder SI125BX50 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX50 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX50 |
| Bore size | Ø125 mm |
| Stroke | 50 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 SAI125BX50 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 SAI125BX50 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 SI125BX50
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×50 | 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 SI125BX50 Is Used
Heavy Pressing
Drives stout pressing operations requiring sustained thrust, utilizing the 6136 N push force at 0.5 MPa.
Pallet Handling
Shifts heavy loaded pallets in distribution hubs where the 313 kg vertical lift capacity handles substantial weights.
Stainless Forming
Performs clamping in washdown forming lines, leveraging the SUS304 rod option to resist moisture and corrosion.
Replacing the Airtac SI125 Standard Cylinder SI125BX50 with the SAI125BX50
To replace the SI125BX50, order the SAI125BX50. Verify the ISO 15552 mounting interface, 125 mm bore, 50 mm stroke, and G1/2 port. Because this is a -B variant, ensure the SAI keeps the SUS304 stainless rod for corrosion resistance. This non-magnetic SKU cannot take CS1-B or DS1-B sensors. If sizing down, an 80 mm bore yields 2513 N at 0.5 MPa; sizing up to 160 mm provides 10053 N. For load holding on air loss, the cushion only decelerates; add an external pilot check valve or use the SAIL lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX50
- ✓ 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 SI125BX50 FAQ
Yes, the SI125BX50 is discontinued. The direct replacement is the SAI125BX50. It matches the ISO 15552 mounting interface, 125 mm bore, 50 mm stroke, and G1/2 port, fitting existing fixtures perfectly.
The G1/2 port feeds a cylinder delivering 6136 N push and 5734 N pull at 0.5 MPa. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical max force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX50
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX50 replacement — usually within 7-8 hours.