This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X300S, 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 SI40X300S
The AirTAC SI40 Standard Cylinder SI40X300S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 300mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X300S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke300 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X300S
- 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 SI40X300S
The AirTAC SI40X300S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 300mm stroke. Delivering 628N push force at 0.5MPa, it is replaced by the SAI40X300S. This direct upgrade shares the exact G1/4 port, M12x1.25 thread, and mounting interface.
The SAI features upgraded two Y-shaped piston seals for low start-up pressure. The SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S magnet works with CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40X300S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X300S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X300S |
| Bore size | Ø40 mm |
| Stroke | 300 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 SAI40X300S 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 SAI40X300S 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 SI40X300S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×300 | 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 SI40X300S Is Used
Package Diversion
Ideal for pushing medium-weight cartons off a main conveyor line using the 628N push force at 0.5 MPa over a 300mm reach.
Pallet Stopper Gate
Functions as a 300mm stroke actuating gate or stopper arm in pallet flow lanes, benefiting from the ISO 15552 mounting interface.
Replacing the Airtac SI40 Standard Cylinder SI40X300S with the SAI40X300S
To replace the SI40X300S, order the SAI40X300S. Verify your ISO 15552 mounting accessories (LB, FA, TC, etc.), the G1/4 air port, and the -S magnet for CS1-B/DS1-B sensors. At 0.5MPa, the 40mm bore yields 628N push and 528N pull; if undersized, the 50mm bore offers 982N push. For the 300mm stroke, use an external guide to prevent rod bending and side-load wear. A plain cylinder drifts without air; for load holding, use the SAIL lock variant or a pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X300S
- ✓ 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 SI40X300S FAQ
Yes, the SI40X300S is discontinued. The direct replacement is the SAI40X300S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 300mm stroke, 628N force, G1/4 port, and mounting interface.
This double-acting cylinder has a 16mm rod, M12x1.25 thread, 27mm cushion, and operates at 30-800 mm/s. Force ratings are: 628N push / 528N pull at 0.5 MPa, 879N push at 0.7 MPa, 1130N push at 0.9 MPa, and a max force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X300S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X300S replacement — usually within 7-8 hours.