This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X125N, 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 SI40X125N
The AirTAC Airtac SI40 Standard Cylinder SI40X125N is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X125N, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X125N
- 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 SI40X125N
The AirTAC SI40X125N is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 125mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the SAI40X125N. This direct upgrade matches the exact ISO 15552 mounting interface, bore, stroke, force and accessories. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
This specific configuration lacks a magnet (-S), meaning it cannot accept CS1-B/DS1-B legacy sensors for position detection. It uses an NBR (-N) seal, operating between -20 and +70 C. Note that a plain cylinder drifts on air loss; the air cushion only decelerates near stroke end. For held loads, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants the SI line lacked.
Airtac SI40 Standard Cylinder SI40X125N Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X125N |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X125N |
| Bore size | Ø40 mm |
| Stroke | 125 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 SAI40X125N 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 SAI40X125N 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 SI40X125N
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×125 | 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 SI40X125N Is Used
Component Clamping
Secures medium-duty workpieces during machining, utilising the 628N push force at 0.5MPa for firm, stable holding.
Package Diverting
Actuates sorting gates on assembly lines, where the 125mm stroke provides precise travel without excessive cycle time.
Replacing the Airtac SI40 Standard Cylinder SI40X125N with the SAI40X125N
To replace the discontinued SI40X125N, order the SAI40X125N. Confirm the ISO 15552 mounting interface (LB, FA, TC, etc.), the 125mm stroke, and the G1/4 port. Because this SKU has no magnet, it cannot support switches; if sensing is needed, order an SAI40X125NS. Sizing both ways: the 40mm bore yields 628N push at 0.5MPa, while the neighbouring 50mm bore offers 982N. A plain cylinder does not hold load without live air; for load holding choose the SAIL (air-released lock) or BSAI (clamp-lock) variants, or fit an external pilot check valve. The SAI family also adds the SAIF variant with a built-in 4M valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X125N
- ✓ 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 SI40X125N FAQ
Yes, the SI40X125N is discontinued. The direct replacement is the AirTAC SAI40X125N. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 125mm stroke, G1/4 port, output force and mounting interface. You simply order the SAI40X125N for your existing fixtures.
This double-acting cylinder features a 16mm rod, M12x1.25 rod thread, 27mm adjustable air cushion, and operates at 30-800 mm/s. Force ratings are: 628N push / 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X125N
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X125N replacement — usually within 7-8 hours.