This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX125S, 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 SI50BX125S
The AirTAC Airtac SI50 Standard Cylinder SI50BX125S 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 SAI50BX125S, 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 → SAI50BX125S
- 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 SI50BX125S
The AirTAC SI50BX125S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 125mm stroke, and a SUS304 stainless piston rod. Delivering 982 N push at 0.5 MPa through a G1/4 port, it is replaced by the SAI50BX125S. This direct successor matches the exact ISO 15552 mounting interface, force, and dimensions.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The -S magnet pairs with CS1-B/DS1-B sensors, while the SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI50 Standard Cylinder SI50BX125S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX125S |
| 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 SAI50BX125S 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 SAI50BX125S 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 SI50BX125S
| 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 SI50BX125S Is Used
Stainless Rod Diverter
Ideal for pushing packages on a line where the SUS304 rod resists washdown moisture.
Mid-Force Clamp
Generates 1374 N at 0.7 MPa to secure medium workpieces during machining.
Replacing the Airtac SI50 Standard Cylinder SI50BX125S with the SAI50BX125S
To replace the SI50BX125S, order the SAI50BX125S, confirming the ISO 15552 interface, 50mm bore, 125mm stroke, G1/4 port, and SUS304 rod. The -S magnet allows CS1-B/DS1-B switches. Sizing both ways: a 63mm bore yields 1559 N at 0.5 MPa, while a 40mm bore yields 628 N. For load holding, note that a plain cylinder drifts without live air and the cushion only decelerates; use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX125S
- ✓ 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 SI50BX125S FAQ
Yes, the SI50BX125S is discontinued. The direct replacement is the SAI50BX125S. It shares the same ISO 15552 mounting interface, 50mm bore, 125mm stroke, force, G1/4 port, and SUS304 stainless rod, fitting existing fixtures perfectly.
It features a G1/4 air port and delivers a push force of 982 N and pull of 825 N at 0.5 MPa. At 0.7 MPa push is 1374 N, and the theoretical maximum is 200 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX125S replacement — usually within 7-8 hours.