This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X540S, 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 SI125 Standard Cylinder SI125X540S
The AirTAC SI125 Standard Cylinder SI125X540S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 540mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X540S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke540 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X540S
- 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 SI125 Standard Cylinder SI125X540S
The AirTAC SI125X540S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 540 mm stroke. Delivering 6136 N push force at 0.5 MPa via a G1/2 port, it is replaced by the SAI125X540S. This direct successor matches the original bore, stroke, force, port, and ISO 15552 mounting interface exactly, fitting existing fixtures seamlessly.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also introduces SAIL, SAIF, and BSAI lock variants unavailable in the SI line. This SI125X540S includes a magnet for CS1-B/DS1-B sensors, while the SAI replacement uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X540S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X540S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X540S |
| Bore size | Ø125 mm |
| Stroke | 540 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125X540S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125X540S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125X540S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×540 | 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 SI125 Standard Cylinder SI125X540S Is Used
Heavy Press Operations
Drives large stamping or forming presses requiring substantial thrust, utilizing the 6136 N push force at 0.5 MPa to move heavy tooling.
Pallet Lift Gates
Actuates heavy-duty lifting gates or scissor lifts where the 540 mm stroke and 313 kg vertical lift capacity handle substantial material loads.
Large Clamp Fixtures
Secures oversized components in machining fixtures, holding parts firmly in place under high clamping pressure.
Replacing the Airtac SI125 Standard Cylinder SI125X540S with the SAI125X540S
To replace the SI125X540S, order the SAI125X540S. Confirm the ISO 15552 mounting interface, 125 mm bore, 540 mm stroke, G1/2 port (PT/G/NPT thread options), and mounting accessory. The built-in magnet (-S) means you can use position sensors; legacy CS1-B/DS1-B switches fit the SI, while the SAI takes current AirTAC sensors. If sizing down, a 100 mm bore yields 3927 N push at 0.5 MPa; sizing up to 160 mm provides 10053 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding consider an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 540 mm, prevent rod bending by guiding the load externally to avoid side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X540S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125X540S FAQ
Yes, the SI125X540S is discontinued. The direct replacement is the SAI125X540S. It shares the same ISO 15552 mounting interface, 125 mm bore, 540 mm stroke, output force, and G1/2 port, fitting directly into existing setups.
This double-acting cylinder has a G1/2 port. It delivers 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical max force of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X540S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X540S replacement — usually within 7-8 hours.