This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X350S, 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 SI50X350S
The AirTAC Airtac SI50 Standard Cylinder SI50X350S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 350mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X350S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke350 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X350S
- 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 SI50X350S
The AirTAC SI50X350S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 350 mm stroke. It delivers 982 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X350S, a direct upgrade sharing the exact ISO 15552 mounting interface, bore, stroke, force, port and mounting accessories.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL, SAIF and BSAI lock variants the SI lacked. Your -S suffix means a piston magnet for CS1-B/DS1-B switches.
Airtac SI50 Standard Cylinder SI50X350S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X350S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X350S |
| Bore size | Ø50 mm |
| Stroke | 350 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 SAI50X350S 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 SAI50X350S 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 SI50X350S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×350 | 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 SI50X350S Is Used
Package Diverting
Drives diverter arms on packaging lines, utilizing the 350 mm stroke to route boxes smoothly between parallel conveyor belts.
Parts Ejection
Pushes machined components out of CNC fixtures, relying on the 982 N push force at 0.5 MPa to clear metal chips freely.
Replacing the Airtac SI50 Standard Cylinder SI50X350S with the SAI50X350S
To replace the SI50X350S, order the SAI50X350S. Verify the ISO 15552 mounting interface, 50 mm bore, 350 mm stroke, G1/4 port (PT/G/NPT thread), and mounting accessory. The -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. Sizing both ways: a 40 mm bore yields 628 N push, while a 63 mm bore yields 1559 N at 0.5 MPa. Because this is a 350 mm stroke, use an external guide to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X350S
- ✓ 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 SI50X350S FAQ
Yes, the AirTAC SI50X350S is discontinued. The direct replacement is the SAI50X350S. It shares the exact ISO 15552 mounting interface, 50 mm bore, 350 mm stroke, output force, G1/4 port and mounting accessories, fitting existing fixtures perfectly.
This 50 mm bore double-acting cylinder uses a G1/4 air port. It delivers 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 max force of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X350S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X350S replacement — usually within 7-8 hours.