This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX300S, 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 SI40BX300S
The AirTAC SI40 Standard Cylinder SI40BX300S 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 SAI40BX300S, 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 → SAI40BX300S
- 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 SI40BX300S
The AirTAC SI40BX300S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 300mm stroke, and a SUS304 stainless steel rod. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40BX300S, matching the interface, force, and mounting.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure. The SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40BX300S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX300S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX300S |
| 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 SAI40BX300S 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 SAI40BX300S 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 SI40BX300S
| 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 SI40BX300S Is Used
Stainless Rod Diverting
Ideal for pushing light packages on a washdown line where the SUS304 rod resists corrosion.
Extended Reach Gating
The 300mm stroke handles wide part ejection, requiring external guides to manage side loads.
Replacing the Airtac SI40 Standard Cylinder SI40BX300S with the SAI40BX300S
To replace the SI40BX300S, order the SAI40BX300S keeping the 40mm bore, 300mm stroke, -B SUS304 rod, -S magnet, and G1/4 port. The SAI is dimensionally interchangeable per ISO 15552. For sizing, a 32mm bore yields 402N push, while a 50mm bore yields 982N at 0.5MPa. The built-in magnet works with legacy CS1-B/DS1-B sensors. Because the 300mm stroke is long, use an external guide to prevent rod bending. Note that a plain cylinder drifts on air loss; for load holding, use an external rod lock or pilot check valve, or specify the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX300S
- ✓ 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 SI40BX300S FAQ
Yes, the SI40BX300S is discontinued. The direct replacement is the SAI40BX300S. It is dimensionally interchangeable per ISO 15552, offering the same 40mm bore, 300mm stroke, 628N force, and G1/4 port.
This 40mm bore cylinder uses a G1/4 port. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, and 1130N push at 0.9MPa. The theoretical maximum force is 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX300S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX300S replacement — usually within 7-8 hours.