This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X303SN, 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 SI125X303SN
The AirTAC SI125 Standard Cylinder SI125X303SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 303mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X303SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke303 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X303SN
- 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 SI125X303SN
The AirTAC SI125X303SN is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 303 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125X303SN, matching the interface, force, and stroke.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. It adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125X303SN Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X303SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X303SN |
| Bore size | Ø125 mm |
| Stroke | 303 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 SAI125X303SN 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 SAI125X303SN 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 SI125X303SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×303 | 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 SI125X303SN Is Used
Heavy Pressing
Drives large stamping and forming presses requiring 8590 N output at 0.7 MPa.
Pallet Diverting
Actuates heavy-duty pallet stops and diverters along high-capacity packaging lines.
Replacing the Airtac SI125 Standard Cylinder SI125X303SN with the SAI125X303SN
To replace the SI125X303SN, order the SAI125X303SN direct, confirming the ISO 15552 mounting interface, G1/2 port, M27x2 thread, and -S magnet for current AirTAC switches. The 303 mm stroke requires external guides to prevent rod bending and side loads. For sizing, neighboring bores offer different forces: 100 mm yields 3927 N push at 0.5 MPa, while 160 mm yields 10053 N. Note that plain cylinders drift without air; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X303SN
- ✓ 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 SI125X303SN FAQ
Yes, the SI125X303SN is discontinued. The direct replacement is the SAI125X303SN, matching the ISO 15552 mounting interface, bore, stroke, force, and port.
It has a G1/2 port. Force ratings are 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N at 0.9 MPa, and a max of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X303SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X303SN replacement — usually within 7-8 hours.