This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X70S, 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 SI125X70S
The AirTAC SI125 Standard Cylinder SI125X70S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 70mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X70S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke70 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X70S
- 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 SI125X70S
The AirTAC SI125X70S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 70 mm stroke, delivering 6136 N push force at 0.5 MPa. 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 legacy unit with the SAI125X70S.
The SAI125X70S is a direct replacement matching the exact ISO 15552 mounting interface, bore, stroke, force, and port. It upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life. For high heat, Viton H seals raise the temperature limit to 150 C.
Airtac SI125 Standard Cylinder SI125X70S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X70S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X70S |
| Bore size | Ø125 mm |
| Stroke | 70 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 SAI125X70S 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 SAI125X70S 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 SI125X70S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×70 | 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 SI125X70S Is Used
Heavy Stamping Press
Drives heavy tooling assemblies in automated stamping lines, utilizing the 6136 N push force to form and seat metal components securely.
Pallet Positioning
Shifts loaded pallets laterally on heavy-duty conveyors, where the 313 kg vertical lift capacity and short 70 mm stroke provide precise indexing.
Large Mold Clamping
Secures large industrial molds during injection or casting processes, relying on the 125 mm bore's substantial thrust and rigid profile barrel.
Replacing the Airtac SI125 Standard Cylinder SI125X70S with the SAI125X70S
To replace the SI125X70S, order the SAI125X70S and confirm the ISO 15552 mounting interface, G1/2 port, and 70 mm stroke. Because the -S suffix indicates a magnet, specify your sensor choice; the legacy SI used CS1-B/DS1-B switches, while the SAI family uses current AirTAC switches. If sizing down, the 100 mm bore yields 3927 N push at 0.5 MPa; if sizing up, the 160 mm bore yields 10053 N. Remember that a plain cylinder drifts without live air, as the cushion only decelerates near stroke end. For load holding, use an external pilot check valve or explore the SAIL (air-released lock) and BSAI (clamp-lock) variants. Rod material options include carbon steel, SUS420J2, or SUS304.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X70S
- ✓ 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 SI125X70S FAQ
Yes, the SI125X70S is discontinued. The direct replacement is the SAI125X70S. It retains the identical ISO 15552 mounting interface, 125 mm bore, 70 mm stroke, output force, and G1/2 port, fitting existing fixtures perfectly while upgrading the piston seal.
The 125 mm bore delivers 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 max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s, with a 40 mm adjustable air cushion at both ends.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X70S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X70S replacement — usually within 7-8 hours.