This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X300LB, 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 SI40X300LB
The AirTAC SI40 Standard Cylinder SI40X300LB 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 SAI40X300LB, 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 → SAI40X300LB
- 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 SI40X300LB
The AirTAC SI40X300LB is a discontinued double-acting ISO 15552 profile cylinder with an LB foot mount. Built for a 40 mm bore and 300 mm stroke, it delivers 628 N push and 528 N pull at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X300LB, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, output force, and porting to fit existing fixtures without modification.
The SAI upgrade features a refined piston seal using two Y-shaped one-way elements for low start-up pressure and extended life. Note that this specific SKU lacks a magnet (-S) and therefore cannot accept position sensors like the legacy CS1-B or DS1-B switches.
Airtac SI40 Standard Cylinder SI40X300LB Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X300LB |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X300LB |
| 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 SAI40X300LB 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 SAI40X300LB 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 SI40X300LB
| 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 SI40X300LB Is Used
Package Diverting
Actuates diverter arms on packaging lines where 628 N push at 0.5 MPa easily handles moderate carton weights over a 300 mm travel.
Material Stopper Gate
Raises and lowers pallet stop gates using the LB foot mount, relying on the adjustable 27 mm air cushions to decelerate at stroke ends.
Replacing the Airtac SI40 Standard Cylinder SI40X300LB with the SAI40X300LB
To replace the SI40X300LB, order the SAI40X300LB. Confirm the ISO 15552 LB foot mounting, 40 mm bore, 300 mm stroke, and G1/4 port (available in PT, G, or NPT threads). Because this SKU lacks a magnet, it cannot support reed or solid-state switches; if sensing is required, specify an SAI40X300LBS. When sizing, a 32 mm bore offers 402 N push at 0.5 MPa, while a 50 mm bore provides 982 N. At 300 mm stroke, prevent rod bending and premature seal wear by guiding the load externally to avoid side-load forces. A standard cylinder drifts on air loss; for load holding, use an external pilot check valve or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X300LB
- ✓ 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 SI40X300LB FAQ
Yes, the SI40X300LB is discontinued. The direct replacement is the SAI40X300LB. It is dimensionally interchangeable per ISO 15552, retaining the same 40 mm bore, 300 mm stroke, LB foot mount, and G1/4 port, so it drops directly into existing machinery.
This double-acting cylinder has a G1/4 air port. 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 maximum force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X300LB
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X300LB replacement — usually within 7-8 hours.