This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X25H, 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 SI40X25H
The AirTAC Airtac SI40 Standard Cylinder SI40X25H is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X25H, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X25H
- 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 SI40X25H
The AirTAC SI40X25H is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. Built with an extruded aluminum barrel and adjustable air cushions, it delivers 628N push force at 0.5MPa. This SKU lacks a magnet, meaning it cannot accept a position sensor. Because it is end-of-life, you should order the SAI40X25H direct replacement, which matches the exact bore, stroke, G1/4 port and ISO 15552 mounting interface.
The SAI upgrade retains all dimensions but features a modernized piston seal using two Y-shaped one-way elements for lower start-up pressure and longer life. For high-temperature environments, the -H Viton seal option extends the operating range up to 150C.
Airtac SI40 Standard Cylinder SI40X25H Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X25H |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X25H |
| Bore size | Ø40 mm |
| Stroke | 25 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 SAI40X25H 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 SAI40X25H 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 SI40X25H
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×25 | 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 SI40X25H Is Used
Short-Stroke Clamping
Ideal for holding lightweight machined parts in a fixture, utilizing the 628N push force at 0.5MPa to secure components during milling or drilling operations.
Package Diverting
Provides rapid actuation for sorting small packages on a conveyor line, with the 25mm stroke delivering fast extension and retraction within the 30-800mm/s speed range.
Ejector Mechanism
Suited for pushing finished small parts out of a molding or stamping die, where the short travel and 528N pull force reliably retract the mechanism.
Replacing the Airtac SI40 Standard Cylinder SI40X25H with the SAI40X25H
To replace the discontinued SI40X25H, order the SAI40X25H, confirming the ISO 15552 mounting interface, 40mm bore, 25mm stroke and G1/4 port. Because this specific SKU lacks a magnet (-S), it cannot support legacy CS1-B/DS1-B sensors; if position detection is required, select an SAI40X25S equivalent instead. When sizing, note this bore provides 628N push at 0.5MPa; if more force is needed, the neighboring 50mm bore offers 982N. A plain cylinder does not hold load on air loss—the cushion only decelerates—so for suspended loads use an external pilot check valve or the SAIL/BSAI lock variants. The 25mm stroke is very short, so side-load risks are minimal, but always verify rod-end thread M12x1.25 alignment.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X25H
- ✓ 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 SI40X25H FAQ
Yes, the SI40X25H is discontinued. The direct replacement is the SAI40X25H. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 25mm stroke, output force, G1/4 port and mounting accessories.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum of 128kgf at 1.0MPa.
Request a Quote for the SAI40X25H
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X25H replacement — usually within 7-8 hours.