This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX275S, 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 SI50BX275S
The AirTAC SI50 Standard Cylinder SI50BX275S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 275mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX275S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke275 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX275S
- 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 SI50BX275S
The AirTAC SI50BX275S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 275mm stroke, and a SUS304 stainless piston rod. Delivering 982N push force at 0.5MPa, it is replaced by the SAI50BX275S. This direct successor shares the exact ISO 15552 mounting interface, G1/4 port, and 30mm cushions.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and longevity. The SAI family also adds SAIL, SAIF, and BSAI lock variants. Your -S magnet supports legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50BX275S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX275S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX275S |
| Bore size | Ø50 mm |
| Stroke | 275 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 SAI50BX275S 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 SAI50BX275S 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 SI50BX275S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×275 | 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 SI50BX275S Is Used
Stainless Rod Actuation
Leverages the SUS304 rod for corrosion-resistant pushing in washdown or mildly chemical manufacturing environments.
Mid-Stroke Diversion
Uses the 275mm stroke to push packages between parallel conveyor lines without requiring full 300mm travel.
Replacing the Airtac SI50 Standard Cylinder SI50BX275S with the SAI50BX275S
To replace the SI50BX275S, order the SAI50BX275S, verifying the ISO 15552 interface, G1/4 port, M16x1.5 thread, and -S magnet for CS1-B/DS1-B switches. The 275mm stroke requires checking side-load and rod-bending limits; use guide rails to prevent binding. For higher force, the 63mm bore offers 1559N at 0.5MPa; for lower force, the 40mm bore gives 628N. A plain cylinder drifts on air loss as cushions only decelerate. For load holding, use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX275S
- ✓ 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 SI50BX275S FAQ
Yes, the SI50BX275S is discontinued. The direct replacement is the SAI50BX275S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 275mm stroke, G1/4 port, and mounting fixtures.
It features a G1/4 air port. The force ratings are 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical maximum of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX275S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX275S replacement — usually within 7-8 hours.