This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X50SFA, 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 SI125X50SFA
The AirTAC Airtac SI125 Standard Cylinder SI125X50SFA 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 SAI125X50SFA, 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 → SAI125X50SFA
- 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 SI125X50SFA
The AirTAC SI125X50SFA is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 50 mm stroke, FA flange mount, and a piston magnet for position sensing. Built for heavy-duty thrust, it delivers 6136 N push and 5734 N pull at 0.5 MPa through a G1/2 port. AirTAC replaced this legacy unit with the SAI125X50SFA, a direct upgrade retaining the exact ISO 15552 mounting interface, M27x2 rod thread, and 40 mm cushions.
The SAI successor introduces an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and extended life. The SAI family also adds SAIL and BSAI lock variants absent from the SI line, while your existing CS1-B/DS1-B legacy sensors map to current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X50SFA Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X50SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X50SFA |
| 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 SAI125X50SFA 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 SAI125X50SFA 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 SI125X50SFA
| 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 SI125X50SFA Is Used
Heavy Pressing
Drives large stamping or forming tools requiring 6136 N of push force at 0.5 MPa within a compact 50 mm stroke.
Clamp Actuation
Secures heavy industrial workpieces using the FA flange mount to withstand high side-load forces during machining.
Vertical Plunging
Pushes assemblies downward in automated lines, relying on adjustable 40 mm cushions to decelerate at stroke end.
Replacing the Airtac SI125 Standard Cylinder SI125X50SFA with the SAI125X50SFA
To replace the SI125X50SFA, order the SAI125X50SFA. Verify your ISO 15552 FA flange mounting bolts, the 50 mm stroke, the G1/2 air port, and the M27x2 rod-end thread. Because this is a 125 mm bore, operating speed is 30-500 mm/s. If you need to size both ways, neighboring bores are 100 mm (3927 N push @0.5 MPa) and 160 mm (10053 N push @0.5 MPa). A plain cylinder does not hold load on air loss—the cushion only decelerates—so for vertical or suspended loads use an external pilot check valve or the SAIL/BSAI lock variant. The -S magnet allows sensor placement; if you ever order a no-S SKU, it cannot accept a sensor.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X50SFA
- ✓ 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 SI125X50SFA FAQ
Yes, the SI125X50SFA is discontinued. The direct replacement is the SAI125X50SFA. It shares the identical ISO 15552 mounting interface, 125 mm bore, 50 mm stroke, G1/2 port, and FA flange, fitting your existing fixtures perfectly.
The G1/2 port feeds a 32 mm rod delivering 6136 N push and 5734 N pull at 0.5 MPa. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical max force is 1251 kgf at 1.0 MPa, with a speed range of 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X50SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X50SFA replacement — usually within 7-8 hours.