This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX250S, 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 SI50BX250S
The AirTAC SI50 Standard Cylinder SI50BX250S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX250S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX250S
- 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 SI50BX250S
The AirTAC SI50BX250S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 250mm stroke, and a SUS304 stainless piston rod. It delivers 982 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI50BX250S, a direct replacement retaining the exact ISO 15552 mounting interface, G1/4 port, and 30 mm cushions. The SAI features an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life.
This SI50BX250S includes a piston magnet for CS1-B/DS1-B legacy sensors. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, consider an external pilot check valve or the SAIL lock variant.
Airtac SI50 Standard Cylinder SI50BX250S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX250S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX250S |
| Bore size | Ø50 mm |
| Stroke | 250 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 SAI50BX250S 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 SAI50BX250S 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 SI50BX250S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×250 | 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 SI50BX250S Is Used
Stainless Rod Diverters
Ideal for packaging lines where the SUS304 rod resists washdown moisture while pushing 50 kg loads between conveyor belts.
Assembly Press Stations
Delivers 982 N of push force at 0.5 MPa to seat components firmly, with adjustable 30 mm cushions for smooth end-of-stroke deceleration.
Replacing the Airtac SI50 Standard Cylinder SI50BX250S with the SAI50BX250S
To replace the SI50BX250S, order the SAI50BX250S. Confirm the ISO 15552 mounting interface, 50mm bore, 250mm stroke, G1/4 port, and M16x1.5 rod thread. Because this unit has the -S magnet and -B SUS304 rod, specify those options. At 250mm stroke, guide external rods to prevent side-load bending. If you need more force, the 63mm bore offers 1559 N at 0.5 MPa; if less is needed, the 40mm bore provides 628 N. Remember that standard cylinders do not hold load without live air—use an external rod lock or pilot check valve, or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX250S
- ✓ 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 SI50BX250S FAQ
Yes, the SI50BX250S is discontinued. The direct replacement is the SAI50BX250S. It shares the same ISO 15552 mounting interface, 50mm bore, 250mm stroke, G1/4 port, and output force, fitting existing fixtures perfectly.
The bore is 50mm with a G1/4 air port. Force output is 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX250S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX250S replacement — usually within 7-8 hours.