This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X820S, 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 SI40 Standard Cylinder SI40X820S
The AirTAC Airtac SI40 Standard Cylinder SI40X820S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 820mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X820S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke820 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X820S
- 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 SI40 Standard Cylinder SI40X820S
The AirTAC SI40X820S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 820 mm stroke. It delivers 628 N push and 528 N pull at 0.5 MPa, operating at 30-800 mm/s through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X820S, a direct sharing the exact mounting interface, bore, stroke, force, and port size.
The SAI upgrade features a new 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 magnet works with legacy CS1-B/DS1-B sensors, though SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X820S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X820S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X820S |
| Bore size | Ø40 mm |
| Stroke | 820 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X820S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X820S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X820S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×820 | 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 SI40 Standard Cylinder SI40X820S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines with a safe 377 N working load, utilizing the 820 mm reach to span wide conveyor belts.
Automated Door Actuation
Opens large machine access doors using the 628 N thrust at 0.5 MPa, with adjustable cushions to soften the end-of-stroke impact.
Replacing the Airtac SI40 Standard Cylinder SI40X820S with the SAI40X820S
To replace the SI40X820S, order the SAI40X820S. Confirm the ISO 15552 mounting interface (LB, FA, CA, TC, etc.), the 820 mm stroke, G1/4 port, and M12x1.25 rod thread. If you need less force, a 32 mm bore gives 402 N push; if you need more, a 50 mm bore yields 982 N. Because this is an 820 mm stroke, prevent rod bending by guiding the load externally to avoid side loads. A plain cylinder drifts without air and the cushion only decelerates; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X820S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X820S FAQ
Yes, the SI40X820S is discontinued. The direct replacement is the SAI40X820S. It shares the identical ISO 15552 mounting interface, 40 mm bore, 820 mm stroke, output force, and G1/4 port, so it fits existing fixtures directly.
The G1/4 port feeds a 16 mm rod. It generates 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical max of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X820S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X820S replacement — usually within 7-8 hours.