This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X770S, 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 SI125X770S
The AirTAC SI125 Standard Cylinder SI125X770S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 770mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X770S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke770 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X770S
- 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 SI125X770S
The AirTAC SI125X770S is a discontinued double-acting ISO 15552 profile cylinder. Delivering 6136 N push force at 0.5 MPa through a 125 mm bore and 770 mm stroke, it features a G1/2 port, M27x2 rod thread, and a 40 mm adjustable air cushion at each end. The direct replacement is the SAI125X770S, which matches the ISO 15552 mounting interface, output, and porting exactly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The original SI-SKU includes a piston magnet for CS1-B/DS1-B sensors, while the SAI family adds lock and valve variants like the SAIL and BSAI that the SI lacked.
Airtac SI125 Standard Cylinder SI125X770S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X770S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X770S |
| Bore size | Ø125 mm |
| Stroke | 770 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 SAI125X770S 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 SAI125X770S 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 SI125X770S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×770 | 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 SI125X770S Is Used
Heavy Material Lifts
Drives large vertical lifting gates or heavy material handling platforms where the 6136 N push force at 0.5 MPa easily moves substantial payloads.
Large Press Actuation
Actuates heavy-duty pressing or stamping assemblies, utilizing the 770 mm stroke for deep reach and the 40 mm cushion to decelerate at stroke ends.
Pallet Positioning
Indexes heavy pallets or large totes along conveyor lines, requiring the robust 32 mm piston rod and G1/2 air port for high flow and stability.
Replacing the Airtac SI125 Standard Cylinder SI125X770S with the SAI125X770S
To replace the SI125X770S, order the SAI125X770S. It is dimensionally interchangeable per ISO 15552, meaning it drops directly into existing fixtures with the same 125 mm bore, 770 mm stroke, G1/2 port, and mounting accessories. Verify your thread option (PT, G, or NPT) and mounting type (LB, FA, TC, etc.). Because this is a 770 mm stroke, use external guides to prevent rod bending and side-load damage. If sizing down, a 100 mm bore gives 3927 N at 0.5 MPa; sizing up to 160 mm provides 10053 N. Note that a standard cylinder drifts without air; for load holding, use an external rod lock, a pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X770S
- ✓ 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 SI125X770S FAQ
Yes, the SI125X770S is discontinued. The direct replacement is the SAI125X770S. It shares the exact same ISO 15552 mounting interface, 125 mm bore, 770 mm stroke, output force, and G1/2 port, fitting your existing fixtures perfectly.
This double-acting cylinder operates at 30-500 mm/s. At 0.5 MPa it provides 6136 N push and 5734 pull force. At 0.7 MPa it pushes 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X770S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X770S replacement — usually within 7-8 hours.