This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X250, 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 SI50X250
The AirTAC Airtac SI50 Standard Cylinder SI50X250 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 SAI50X250, 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 → SAI50X250
- 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 SI50X250
The AirTAC SI50X250 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 250mm stroke. It delivers a thrust of 982 N at 0.5 MPa, utilizing a G1/4 air port and a 20mm piston rod. AirTAC replaced this legacy unit with the SAI50X250, a direct replacement sharing the exact ISO 15552 mounting interface, force output, and dimensions.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. For applications needing load holding on air loss, the SAI family introduces SAIL and BSAI lock variants absent in the SI line. Note this non-magnet SKU cannot accept position sensors.
Airtac SI50 Standard Cylinder SI50X250 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X250 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X250 |
| 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 SAI50X250 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 SAI50X250 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 SI50X250
| 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 SI50X250 Is Used
Package Diverting
Drives diverter arms on sorting lines, using the 250mm stroke to push parcels cleanly between adjacent conveyor belts without collision.
Pallet Stops
Acts as a pneumatic stop gate for pallets entering a wrapping station, holding steady against 50 kg loads at 0.5 MPa operating pressure.
Clamp Actuation
Moves short-stroke clamping jaws to secure aluminum extrusions for cutting, relying on the 982 N push force to prevent workpiece slip.
Replacing the Airtac SI50 Standard Cylinder SI50X250 with the SAI50X250
To replace the SI50X250, order the SAI50X250. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port thread (PT/G/NPT), and the M16x1.5 rod-end connection. Because this SKU lacks a magnet, it cannot support CS1-B/DS1-B sensors; add the -S suffix on the SAI order if sensing is needed. Sizing checks: a 40mm bore yields 628 N push at 0.5 MPa, while a 63mm bore yields 1559 N, giving you room to adjust if fixture loads change. A plain cylinder drifts on air loss—the cushion only decelerates—so use an external pilot check valve or the SAIL lock variant for holding. At 250mm stroke, guide external loads to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X250
- ✓ 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 SI50X250 FAQ
Yes, the SI50X250 is discontinued. The direct replacement is the SAI50X250. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 250mm stroke, 982 N force, G1/4 port, and mounting interface, so it drops right into existing fixtures.
This double-acting cylinder uses a G1/4 air port. At 0.5 MPa it provides 982 N push and 825 N pull force. At 0.7 MPa push is 1374 N, and at 0.9 MPa it is 1767 N. The theoretical maximum force is 200 kgf at 1.0 MPa.
Request a Quote for the SAI50X250
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X250 replacement — usually within 7-8 hours.