This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX300S, 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 SI125AX300S
The AirTAC SI125 Standard Cylinder SI125AX300S 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 SAI125AX300S, 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 → SAI125AX300S
- 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 SI125AX300S
The AirTAC SI125AX300S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 300mm stroke. It delivers 6136N push and 5734N pull at 0.5MPa, utilizing a G1/2 port and an M27x2 rod thread. The direct replacement is the SAI125AX300S, matching the ISO 15552 mounting interface, output force, and stroke.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This -A variant uses a SUS420J2 stainless rod for corrosion resistance, while the -S magnet supports CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125AX300S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX300S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX300S |
| 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 SAI125AX300S 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 SAI125AX300S 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 SI125AX300S
| 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 SI125AX300S Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136N push force at 0.5MPa to hold components rigidly against the tooling bed.
Pallet Stopper Gate
Acts as a high-force stopping barrier on heavy-duty conveyor lines, reliably halting loaded pallets before the packaging station.
Material Lift Lowering
Drives heavy material handling lifts downward, where the 5734N pull force at 0.5MPa safely manages the descent of substantial payloads.
Replacing the Airtac SI125 Standard Cylinder SI125AX300S with the SAI125AX300S
To replace the SI125AX300S, order the SAI125AX300S. Verify the ISO 15552 mounting interface, 300mm stroke, G1/2 port, and your specific mounting accessory (LB, FA, TC, etc.). The -S magnet enables current AirTAC switches (replacing legacy CS1-B/DS1-B), and the -A rod is SUS420J2 stainless. If you need to size up or down, neighboring bores (100mm or 160mm) offer different force classes (3927N or 10053N push at 0.5MPa). Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. Because the 300mm stroke is long, use external guides to prevent rod bending and side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX300S
- ✓ 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 SI125AX300S FAQ
Yes, the SI125AX300S is discontinued. The direct replacement is the SAI125AX300S. It is dimensionally interchangeable per ISO 15552, offering the same 125mm bore, 300mm stroke, G1/2 port, and mounting interface.
The 125mm bore provides 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical max of 1251kgf at 1.0MPa. Operating speed is 30-500mm/s. It uses a G1/2 port and M27x2 rod thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX300S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX300S replacement — usually within 7-8 hours.