This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX125, 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 SI50 Standard Cylinder SI50BX125
The AirTAC Airtac SI50 Standard Cylinder SI50BX125 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX125, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX125
- 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 SI50 Standard Cylinder SI50BX125
The AirTAC SI50BX125 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 125mm stroke, delivering 982N push force at 0.5 MPa via a G1/4 port. It is replaced by the direct replacement SAI50BX125.
The SAI upgrade retains the exact ISO 15552 mounting interface, force, and dimensions, but introduces an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. Because this specific SKU lacks a magnet (-S), it cannot accept position switches like the legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50BX125 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX125 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX125 |
| Bore size | Ø50 mm |
| Stroke | 125 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50BX125 carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50BX125 produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50BX125
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×125 | 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 SI50 Standard Cylinder SI50BX125 Is Used
Package Diverting
Pushes medium-weight cartons off a main conveyor line using 982N of thrust at 0.5 MPa without requiring position feedback.
Clamp Actuation
Holds aluminum extrusions in place during machining operations, relying on the 125mm stroke to clear the work area.
Pallet Stops
Acts as a pneumatic stop gate for incoming pallets, using the 30mm adjustable air cushions to decelerate the load smoothly.
Replacing the Airtac SI50 Standard Cylinder SI50BX125 with the SAI50BX125
To replace the SI50BX125, order the SAI50BX125 ensuring the ISO 15552 interface, 50mm bore, 125mm stroke, G1/4 port, and mounting accessory match. This non-magnet SKU cannot take sensors; if sensing is needed, order the SAI50BX125S. Sizing both ways: a 40mm bore yields 628N push at 0.5 MPa, while a 63mm bore yields 1559N. Note that a plain cylinder drifts on air loss as the cushion only decelerates; for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The -B rod option specifies SUS304 stainless steel for corrosion resistance.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX125
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50BX125 FAQ
Yes, the SI50BX125 is discontinued. The direct replacement is the SAI50BX125, which maintains the same ISO 15552 mounting interface, 50mm bore, 125mm stroke, output force, and G1/4 port.
It features a G1/4 port and generates 982N push / 825N pull at 0.5 MPa, 1374N push at 0.7 MPa, 1767N push at 0.9 MPa, and a theoretical max of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX125
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX125 replacement — usually within 7-8 hours.