This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X25FA, 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 SI50 Standard Cylinder SI50X25FA
The AirTAC Airtac SI50 Standard Cylinder SI50X25FA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X25FA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X25FA
- 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 SI50 Standard Cylinder SI50X25FA
The AirTAC SI50X25FA is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 25mm stroke, and FA flange mount. Delivering 982N push at 0.5MPa via a G1/4 port, it is replaced by the SAI50X25FA. This direct upgrade retains the exact ISO 15552 mounting interface, bore, stroke, force, and port size for existing fixtures.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. Without a magnet, this SKU cannot take a sensor. For higher heat, Viton H seals raise the temperature range to 0-150C.
Airtac SI50 Standard Cylinder SI50X25FA Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X25FA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X25FA |
| Bore size | Ø50 mm |
| Stroke | 25 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50X25FA carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50X25FA produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50X25FA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×25 | 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 SI50 Standard Cylinder SI50X25FA Is Used
Short-Stroke Clamping
Ideal for 25mm clamping actions in machining fixtures, providing a solid 982N hold at 0.5MPa.
Package Diverting
Snappy 25mm diverting strokes on packaging lines, operating efficiently at 30-800mm/s.
Flange-Mounted Ejection
FA flange mounting secures the cylinder for short, repeatable part ejection tasks in assembly.
Replacing the Airtac SI50 Standard Cylinder SI50X25FA with the SAI50X25FA
To replace the SI50X25FA, order the SAI50X25FA. Confirm the ISO 15552 FA flange interface, 50mm bore, 25mm stroke, and G1/4 port. This SKU lacks a magnet (-S), so it cannot accept CS1-B/DS1-B switches; order an SAI model with S if sensing is needed. For sizing, a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore gives 1559N. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X25FA
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50X25FA FAQ
Yes, the SI50X25FA is discontinued. The direct replacement is the SAI50X25FA, which shares the same ISO 15552 FA flange interface, 50mm bore, 25mm stroke, 982N force, and G1/4 port.
The 50mm bore uses a G1/4 port. At 0.5MPa it pushes 982N and pulls 825N. Push force is 1374N at 0.7MPa and 1767N at 0.9MPa. The theoretical maximum force is 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X25FA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X25FA replacement — usually within 7-8 hours.