This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X650S, 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 SI125X650S
The AirTAC SI125 Standard Cylinder SI125X650S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 650mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X650S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke650 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X650S
- 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 SI125X650S
The AirTAC SI125X650S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 650mm stroke. Generating 6136N push force at 0.5MPa, it features a G1/2 port, M27x2 rod thread, and a built-in piston magnet for legacy CS1-B/DS1-B sensors. AirTAC replaced this end-of-life unit with the SAI125X650S, a direct upgrade sharing the exact ISO 15552 mounting interface, bore, stroke, and force.
The SAI replacement introduces an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also adds variants the SI lacked, like the SAIL air-released lock and BSAI clamp-lock, while offering Viton H seals for high-temperature environments up to 150C.
Airtac SI125 Standard Cylinder SI125X650S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X650S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X650S |
| Bore size | Ø125 mm |
| Stroke | 650 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 SAI125X650S 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 SAI125X650S 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 SI125X650S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×650 | 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 SI125X650S Is Used
Heavy Press Actuation
Drives large press fixtures requiring high force, delivering 6136N at 0.5MPa with smooth adjustable air cushioning at stroke ends.
Large Package Diverters
Actuates heavy-duty diverter arms over a 650mm reach, requiring external load guides to prevent excessive rod bending during transit.
Replacing the Airtac SI125 Standard Cylinder SI125X650S with the SAI125X650S
To replace the discontinued SI125X650S, order the SAI125X650S. Confirm the ISO 15552 mounting interface, 125mm bore, 650mm stroke, G1/2 port (PT/G/NPT thread options), and your specific mounting accessory (LB, FA, TC, etc.). The -S suffix means a magnet is present for CS1-B/DS1-B switches; the SAI replacement uses current AirTAC switches. Sizing both ways: a neighbouring 100mm bore yields 3927N push at 0.5MPa, while a 160mm bore yields 10053N. Note that a plain cylinder does not hold load on air loss—the cushion only decelerates—so use the SAIL/BSAI lock variant or an external pilot check valve for holding. With a 650mm stroke, prevent rod bending by guiding the load externally to minimize side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X650S
- ✓ 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 SI125X650S FAQ
Yes, the SI125X650S is discontinued. The direct replacement is the SAI125X650S. It shares the identical ISO 15552 mounting interface, 125mm bore, 650mm stroke, output force, and G1/2 port, fitting existing fixtures perfectly while upgrading the piston seal.
The 125mm bore uses a G1/2 port. It generates 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X650S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X650S replacement — usually within 7-8 hours.