This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X20S, 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 SI50X20S
The AirTAC Airtac SI50 Standard Cylinder SI50X20S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 20mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X20S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke20 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X20S
- 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 SI50X20S
The AirTAC SI50X20S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 20 mm stroke. It delivers 982 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI50X20S, a direct upgrade retaining the exact ISO 15552 mounting interface, stroke, force, and accessories.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The original -S magnet supports CS1-B/DS1-B sensors, while the SAI family adds lock and valve variants like SAIL and BSAI absent in the SI line.
Airtac SI50 Standard Cylinder SI50X20S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X20S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X20S |
| Bore size | Ø50 mm |
| Stroke | 20 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 SAI50X20S 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 SAI50X20S 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 SI50X20S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×20 | 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 SI50X20S Is Used
Short-Stroke Clamping
Ideal for holding parts during machining, delivering 982 N of clamping force in a compact 20 mm stroke envelope.
Ejector Mechanisms
Provides rapid part ejection on assembly lines, utilizing the 30-800 mm/s speed range and G1/4 air port.
Replacing the Airtac SI50 Standard Cylinder SI50X20S with the SAI50X20S
To replace the SI50X20S, order the SAI50X20S and confirm the ISO 15552 mounting interface, 50 mm bore, 20 mm stroke, G1/4 port, and M16x1.5 rod thread. Keep the -S magnet for current AirTAC switch compatibility. If you need more force, the neighbouring 63 mm bore yields 1559 N at 0.5 MPa; if less is required, the 40 mm bore gives 628 N. Note that a plain cylinder drifts on air loss because the cushion only decelerates—for load holding, use an external pilot check valve or the SAIL/BSAI lock variants. Even at 20 mm stroke, verify rod-bending limits if guiding heavy off-center loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X20S
- ✓ 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 SI50X20S FAQ
Yes, the SI50X20S is discontinued. The direct replacement is the AirTAC SAI50X20S. It is dimensionally interchangeable per ISO 15552, matching the 50 mm bore, 20 mm stroke, G1/4 port, and mounting fixtures.
It features a G1/4 port, a 20 mm rod, and an M16x1.5 thread. Force output is 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Request a Quote for the SAI50X20S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X20S replacement — usually within 7-8 hours.