This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X250SN, 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 SI50X250SN
The AirTAC SI50 Standard Cylinder SI50X250SN 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 SAI50X250SN, 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 → SAI50X250SN
- 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 SI50X250SN
The AirTAC SI50X250SN 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. The direct replacement is the SAI50X250SN, matching the exact interface, force and stroke.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. It also adds SAIL, SAIF and BSAI variants the SI lacked. Your NBR seal handles -20 to +70C, while a Viton H option extends this to 150C. The built-in magnet supports CS1-B/DS1-B switches.
Airtac SI50 Standard Cylinder SI50X250SN Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X250SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X250SN |
| 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 SAI50X250SN 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 SAI50X250SN 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 SI50X250SN
| 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 SI50X250SN Is Used
Package Diverting
Drives diverter arms on sorting lines using the 982N push force to redirect medium weight cartons reliably.
Pallet Gate Control
Actuates safety gates and stops at loading docks where the 50kg vertical lift capacity is sufficient.
Clamp Actuation
Secures workpieces in machining fixtures, utilizing the 250mm stroke to accommodate varying part sizes.
Replacing the Airtac SI50 Standard Cylinder SI50X250SN with the SAI50X250SN
To replace the SI50X250SN, order the SAI50X250SN. Verify the ISO 15552 mounting interface, 50mm bore, 250mm stroke, G1/4 port and your specific mounting accessory. The -S magnet enables CS1-B/DS1-B sensors, while the -N denotes the standard NBR seal. If you need more force, the 63mm bore yields 1559N push at 0.5MPa; if less is required, the 40mm bore provides 628N. At 250mm stroke, ensure adequate guide support to prevent rod bending and side loads. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X250SN
- ✓ 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 SI50X250SN FAQ
Yes, the SI50X250SN is discontinued. The direct replacement is the SAI50X250SN. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 250mm stroke, 982N force, G1/4 port and mounting interface.
The 50mm bore uses a G1/4 port. At 0.5MPa it provides 982N push and 825N pull force. At 0.7MPa push is 1374N, and at 0.9MPa it is 1767N. The theoretical maximum force is 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X250SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X250SN replacement — usually within 7-8 hours.