This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X50FA, 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 SI125X50FA
The AirTAC Airtac SI125 Standard Cylinder SI125X50FA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 50mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X50FA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke50 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X50FA
- 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 SI125X50FA
The AirTAC SI125X50FA is a discontinued double-acting ISO 15552 profile cylinder featuring an extruded aluminum barrel, adjustable air cushions, and an FA flange mounting interface. Delivering 6136 N push force at 0.5 MPa through a 125 mm bore and G1/2 port, this legacy unit is replaced by the SAI125X50FA. The current SAI production line is a direct, matching the exact stroke, force, and mounting footprint.
Upgrading to the SAI125X50FA retains all ratings but introduces an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note this specific SKU lacks a magnet, so it cannot accept CS1-B/DS1-B sensors. If load holding is required, explore the SAIL or BSAI lock variants, as standard cushions only decelerate.
Airtac SI125 Standard Cylinder SI125X50FA Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X50FA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X50FA |
| Bore size | Ø125 mm |
| Stroke | 50 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 SAI125X50FA 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 SAI125X50FA 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 SI125X50FA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×50 | 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 SI125X50FA Is Used
Heavy Press Clamping
Ideal for securing large metal castings or heavy plates in machining fixtures, utilizing the 6136 N push force at 0.5 MPa to maintain rigid clamping during milling or drilling operations.
Pallet Positioning Stops
Functions as a robust physical stop gate on high-capacity pallet conveyors, absorbing kinetic impact from heavy loads while utilizing the FA flange mount for stable structural attachment.
Industrial Door Actuation
Drives the opening and closing of heavy industrial safety doors or blast gates, where the 125 mm bore provides the necessary high torque to move substantial weight against resistance.
Replacing the Airtac SI125 Standard Cylinder SI125X50FA with the SAI125X50FA
To replace the discontinued SI125X50FA, order the SAI125X50FA. Verify your ISO 15552 FA flange mounting dimensions, 125 mm bore, 50 mm stroke, and G1/2 port. Because this SKU has no -S magnet, it cannot support position sensing; if switches are needed, select an SAI equivalent with the magnet option. The 125 mm bore yields 6136 N push at 0.5 MPa; if less force is acceptable, step down to an 80 mm bore (2513 N push), or size up to 160 mm (10053 N) for heavier loads. Remember, a plain cylinder drifts on air loss—the cushion only decelerates. For secure holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X50FA
- ✓ 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 SI125X50FA FAQ
Yes, the AirTAC SI125X50FA is discontinued and end-of-life. The direct replacement is the SAI125X50FA. It features the same ISO 15552 mounting interface, 125 mm bore, 50 mm stroke, G1/2 port, and FA flange mount, fitting existing fixtures perfectly without modifications.
This 125 mm bore cylinder uses a G1/2 air port and a 32 mm piston rod. The thrust outputs are 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 maximum theoretical force of 1251 kgf at 1.0 MPa. It operates at speeds between 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X50FA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X50FA replacement — usually within 7-8 hours.