This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X320S, 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 SI125X320S
The AirTAC SI125 Standard Cylinder SI125X320S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 320mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X320S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke320 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X320S
- 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 SI125X320S
The AirTAC SI125X320S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 320 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. AirTAC replaced this legacy unit with the SAI125X320S, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, output force, and accessories.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. It also adds SAIL and BSAI lock variants absent in the SI line. The -S suffix means it has a piston magnet for CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125X320S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X320S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X320S |
| Bore size | Ø125 mm |
| Stroke | 320 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 SAI125X320S 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 SAI125X320S 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 SI125X320S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×320 | 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 SI125X320S Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136 N push force to hold components rigidly against the fixture.
Pallet Diverting
Actuates heavy-duty diverters on conveyor lines to route loaded pallets, with the 320 mm stroke providing the reach needed to clear adjacent lanes.
Automated Assembly Lifts
Raises substantial sub-assemblies between production tiers, where the 313 kg vertical lift capacity handles heavy industrial frames safely.
Replacing the Airtac SI125 Standard Cylinder SI125X320S with the SAI125X320S
To replace the SI125X320S, order the SAI125X320S and verify the ISO 15552 mounting interface, 125 mm bore, 320 mm stroke, G1/2 port, and M27x2 rod thread. The -S magnet equates to legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. If sizing up or down, neighboring bores (100 mm / 160 mm) offer different force classes; this 125 mm bore yields 6136 N push at 0.5 MPa. A plain cylinder drifts on air loss since the 40 mm adjustable cushion only decelerates near stroke end, so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant for load holding. At 320 mm, prevent rod bending by supporting the load with external guides to minimize side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X320S
- ✓ 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 SI125X320S FAQ
Yes, the SI125X320S is discontinued. The direct replacement is the AirTAC SAI125X320S. It shares the same ISO 15552 mounting interface, 125 mm bore, 320 mm stroke, output force, G1/2 port, and mounting accessories, fitting directly into existing fixtures.
The 125 mm bore features a G1/2 air port, a 32 mm rod, and an M27x2 rod thread. Force 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X320S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X320S replacement — usually within 7-8 hours.