This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX300, 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 SI125AX300
The AirTAC SI125 Standard Cylinder SI125AX300 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 300mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX300, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke300 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX300
- 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 SI125AX300
The AirTAC SI125AX300 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 300 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125AX300, which shares the same ISO 15552 mounting interface, bore, stroke, force, port and accessories.
The SAI upgrade features an improved piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This SI125AX300 variant uses a SUS420J2 stainless steel rod (option A) for corrosion resistance, but lacks a magnet (-S), so it cannot accept a CS1-B/DS1-B sensor.
Airtac SI125 Standard Cylinder SI125AX300 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX300 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX300 |
| Bore size | Ø125 mm |
| Stroke | 300 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 SAI125AX300 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 SAI125AX300 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 SI125AX300
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | 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 SI125 Standard Cylinder SI125AX300 Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136 N push force at 0.5 MPa to hold components rigidly against the fixture.
Bulk Material Diversion
Actuates heavy-duty diverter arms on packaging lines, using the 300 mm stroke to redirect large totes between conveyor belts.
Replacing the Airtac SI125 Standard Cylinder SI125AX300 with the SAI125AX300
To replace the SI125AX300, order the SAI125AX300. Verify the ISO 15552 mounting interface, the 300 mm stroke, the G1/2 port (PT/G/NPT thread options), and your specific mounting accessory (LB, FA, CA, TC, etc.). Because this SKU lacks the -S magnet, it cannot support position sensing; if switches are needed, select an SAI model with the S suffix for current AirTAC switches. When sizing, note the 125 mm bore yields 6136 N push at 0.5 MPa; if less force is acceptable, step down to an 80 mm bore (2513 N push). For load holding, note that a standard cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. Finally, at 300 mm stroke, prevent rod bending by guiding the load externally to avoid side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX300
- ✓ 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 SI125AX300 FAQ
Yes, the AirTAC SI125AX300 is discontinued. The direct replacement is the SAI125AX300. It is dimensionally interchangeable per the ISO 15552 mounting interface, retaining the same 125 mm bore, 300 mm stroke, output force, G1/2 port, and mounting accessories.
This 125 mm bore cylinder features a G1/2 air port and an M27x2 rod thread. The thrust output is 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 maximum of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX300
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX300 replacement — usually within 7-8 hours.