This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X250S, 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 SI50X250S
The AirTAC Airtac SI50 Standard Cylinder SI50X250S 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 SAI50X250S, 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 → SAI50X250S
- 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 SI50X250S
The AirTAC SI50X250S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 250mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X250S, a direct upgrade retaining the exact interface, dimensions, and output force.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note that plain cylinders drift without live air; for held loads, explore the SAIL lock or BSAI clamp-lock variants the SI line lacked.
Airtac SI50 Standard Cylinder SI50X250S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X250S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X250S |
| 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 SAI50X250S 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 SAI50X250S 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 SI50X250S
| 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 SI50X250S Is Used
Package Diverting
Drives diverting arms on packaging lines where the 982N push force at 0.5MPa easily redirects standard cartons.
Material Lowering
Controls the descent of light material lifts, using the 30mm adjustable air cushion to decelerate the 250mm stroke smoothly.
Clamp Actuation
Actuates secondary clamping fixtures on machining cells, providing reliable holding via the 50mm bore within the 0.15-1.0MPa range.
Replacing the Airtac SI50 Standard Cylinder SI50X250S with the SAI50X250S
To replace the SI50X250S, order the SAI50X250S. Confirm the ISO 15552 mounting interface, the 50mm bore, 250mm stroke, G1/4 port (PT/G/NPT thread options), and the -S magnet for CS1-B/DS1-B legacy sensors (the SAI uses current AirTAC switches). If downsizing, a 40mm bore yields 628N push at 0.5MPa; if upsizing, a 63mm bore provides 1559N. Because the stroke is 250mm, ensure adequate guide support to prevent rod bending and side-load wear. Remember, the adjustable air cushion only decelerates the piston near stroke end—it does not hold the load. For secure load holding without air, use an external pilot check valve, rod lock, or the SAIL/BSAI variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X250S
- ✓ 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 SI50X250S FAQ
Yes, the SI50X250S is discontinued. The direct replacement is the SAI50X250S. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 250mm stroke, output force, G1/4 port, and mounting accessories.
This double-acting cylinder uses a G1/4 air port. The thrust 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 SAI50X250S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X250S replacement — usually within 7-8 hours.