This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X375S, 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 SI40X375S
The AirTAC Airtac SI40 Standard Cylinder SI40X375S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 375mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X375S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke375 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X375S
- 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 SI40X375S
The AirTAC SI40X375S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 375 mm stroke. It delivers 628 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40X375S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, stroke, output force, and port size.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. For applications needing load holding on air loss, the SAI family introduces SAIL and BSAI lock variants absent in the SI line. The built-in magnet supports legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40X375S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X375S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X375S |
| Bore size | Ø40 mm |
| Stroke | 375 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 SAI40X375S 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 SAI40X375S 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 SI40X375S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×375 | 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 SI40X375S Is Used
Package Diversion
Pushes medium-weight cartons off a sorting line using the 628 N push force at 0.5 MPa, with the 375 mm stroke clearing the conveyor width.
Pallet Positioning
Indexes empty pallets into a loading cell, utilizing the G1/4 port and ISO 15552 mounting for rigid fixture integration.
Gate Actuation
Opens and closes access gates on automated machinery where the 32 kg vertical lift capacity easily overcomes the gate weight.
Replacing the Airtac SI40 Standard Cylinder SI40X375S with the SAI40X375S
To replace the discontinued SI40X375S, order the SAI40X375S. Verify the ISO 15552 mounting interface, 40 mm bore, 375 mm stroke, G1/4 port, and M12x1.25 rod thread. The -S suffix indicates a piston magnet for CS1-B/DS1-B switches; the SAI replacement uses current AirTAC switches. For sizing, a 32 mm bore offers 402 N push at 0.5 MPa, while a 50 mm bore yields 982 N. At 375 mm stroke, use external guides to prevent rod bending and side-load wear. A plain cylinder does not hold load without live air; the cushion only decelerates. For secure holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X375S
- ✓ 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 SI40X375S FAQ
Yes, the SI40X375S is discontinued. The direct replacement is the SAI40X375S. It shares the identical ISO 15552 mounting interface, 40 mm bore, 375 mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
It features a G1/4 air port. Force ratings are 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 maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X375S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X375S replacement — usually within 7-8 hours.