This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X520S, 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 SI125X520S
The AirTAC SI125 Standard Cylinder SI125X520S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 520mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X520S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke520 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X520S
- 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 SI125X520S
The AirTAC SI125X520S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 520 mm stroke. Delivering 6136 N push force at 0.5 MPa, it features a G1/2 port, M27x2 rod thread, and a piston magnet for CS1-B/DS1-B sensors. AirTAC replaced this legacy unit with the SAI125X520S. The SAI is a direct: identical ISO 15552 mounting interface, bore, stroke, output force, and porting, so it fits existing fixtures directly.
The SAI upgrade introduces an advanced piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI variants absent from the SI line. Note that a plain cylinder drifts without live air; use SAIL or BSAI for load holding.
Airtac SI125 Standard Cylinder SI125X520S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X520S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X520S |
| Bore size | Ø125 mm |
| Stroke | 520 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 SAI125X520S 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 SAI125X520S 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 SI125X520S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×520 | 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 SI125X520S Is Used
Heavy Pressing
Drives large stamping or forming presses requiring 6136 N push force at 0.5 MPa with stable ISO 15552 mounting.
Pallet Handling
Shifts heavy loaded pallets over 520 mm strokes, benefiting from external guides to manage side loads.
Replacing the Airtac SI125 Standard Cylinder SI125X520S with the SAI125X520S
To replace the SI125X520S, order the SAI125X520S. Confirm the ISO 15552 mounting interface (LB, FA, TC, etc.), the 520 mm stroke, the G1/2 port, and the -S magnet option. The SAI uses current AirTAC switches, replacing the legacy CS1-B/DS1-B sensors. If you need to size both ways, neighboring bores are 100 mm and 160 mm; at 0.5 MPa, this 125 mm bore yields 6136 N push and 5734 N pull. A plain cylinder does not hold load without live air, as the cushion only decelerates. For holding, consider the SAIL lock, BSAI clamp-lock, or an external pilot check valve. Because the 520 mm stroke is long, use external guides to prevent rod bending and side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X520S
- ✓ 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 SI125X520S FAQ
Yes, the AirTAC SI125X520S is discontinued. The direct replacement is the SAI125X520S. It shares the same ISO 15552 mounting interface, 125 mm bore, 520 mm stroke, force, and G1/2 port, fitting directly into existing setups.
At 0.5 MPa, push force is 6136 N and pull is 5734 N. At 0.7 MPa push is 8590 N, and at 0.9 MPa it is 11045 N. The theoretical max is 1251 kgf at 1.0 MPa. It uses a G1/2 port, M27x2 thread, and operates at 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X520S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X520S replacement — usually within 7-8 hours.