This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX120, 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 SI125AX120
The AirTAC SI125 Standard Cylinder SI125AX120 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 120mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX120, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke120 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX120
- 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 SI125AX120
The AirTAC SI125AX120 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 120 mm stroke. It delivers 6136 N push and 5734 N pull at 0.5 MPa, utilizing a G1/2 port and an M27x2 rod thread. The direct replacement is the SAI125AX120, matching the exact ISO 15552 mounting interface, force, and dimensions. This specific SKU features a SUS420J2 stainless steel piston rod for corrosion resistance, but because it lacks a magnet (-S), it cannot accept position sensors.
The SAI125AX120 upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. For applications requiring load holding on air loss, note that a plain cylinder drifts; the 40 mm adjustable air cushions only decelerate the piston near stroke end. You must add an external rod lock or pilot check valve, or step up to the SAIL or BSAI lock variants.
Airtac SI125 Standard Cylinder SI125AX120 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX120 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX120 |
| Bore size | Ø125 mm |
| Stroke | 120 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 SAI125AX120 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 SAI125AX120 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 SI125AX120
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×120 | 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 SI125AX120 Is Used
Heavy Press Clamping
Secures large metal castings in machining fixtures, using the 6136 N push force at 0.5 MPa to hold components firmly against cutting forces.
Pallet Lift Gates
Actuates heavy-duty loading dock gates where the SUS420J2 stainless rod resists humidity, and the 313 kg vertical lift capacity handles substantial gate weight.
Mold Ejection Systems
Drives large injection mold ejector plates, relying on the 40 mm adjustable air cushions to decelerate the 125 mm bore piston smoothly at stroke end.
Replacing the Airtac SI125 Standard Cylinder SI125AX120 with the SAI125AX120
To replace the SI125AX120, order the SAI125AX120. Confirm your ISO 15552 mounting accessory (LB, FA, CA, TC) and the G1/2 port thread (PT, G, or NPT). This unit has an -A stainless steel rod; specify it on the SAI order. Because this SKU lacks the -S magnet, it cannot support legacy CS1-B/DS1-B sensors—if sensing is needed, order the SAI with an -S suffix for current AirTAC switches. Sizing both ways: the 125 mm bore gives 6136 N at 0.5 MPa; dropping to an 80 mm bore yields 2513 N, while increasing to 160 mm provides 10053 N. For any load holding, the cushion only decelerates; use a pilot check valve or the SAIL/BSAI lock variant. For strokes over 300 mm, guide the load to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX120
- ✓ 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 SI125AX120 FAQ
Yes, the SI125AX120 is discontinued. The direct replacement is the SAI125AX120. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 120 mm stroke, 6136 N force, G1/2 port, and mounting interface.
The 125 mm bore uses a G1/2 port. It generates 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 SAI125AX120
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX120 replacement — usually within 7-8 hours.