This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X125SFA, 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 SI50X125SFA
The AirTAC Airtac SI50 Standard Cylinder SI50X125SFA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X125SFA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X125SFA
- 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 SI50X125SFA
The AirTAC SI50X125SFA is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 125mm stroke. It delivers 982 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X125SFA, a direct upgrade retaining the exact ISO 15552 mounting interface, FA flange, and output force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure. It also adds SAIL and BSAI lock variants absent in the SI line. The -S magnet supports CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50X125SFA Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X125SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X125SFA |
| Bore size | Ø50 mm |
| Stroke | 125 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 SAI50X125SFA 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 SAI50X125SFA 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 SI50X125SFA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×125 | 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 SI50X125SFA Is Used
Clamp Actuation
Ideal for mid-tier machining fixtures requiring 982 N of push force at 0.5 MPa to secure parts during milling or drilling operations.
Package Diversion
Provides reliable 125 mm stroke actuation for routing medium-weight goods between conveyor lanes in material handling lines.
Replacing the Airtac SI50 Standard Cylinder SI50X125SFA with the SAI50X125SFA
To replace the SI50X125SFA, order the SAI50X125SFA. Verify the ISO 15552 FA flange interface, 50mm bore, 125mm stroke, G1/4 port, and -S magnet. If you need more force, the 63mm bore yields 1559 N push at 0.5 MPa; if less is required, the 40mm bore provides 628 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAI family also offers the SAIF integrated valve for bores up to 100mm.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X125SFA
- ✓ 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 SI50X125SFA FAQ
Yes, the SI50X125SFA is discontinued. The direct replacement is the SAI50X125SFA. It shares the identical ISO 15552 mounting interface, 50mm bore, 125mm stroke, G1/4 port, and FA flange, fitting existing fixtures perfectly.
It operates at 0.15-1.0 MPa with a G1/4 port and M16x1.5 rod thread. Speed is 30-800 mm/s. Force ratings are: 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a maximum theoretical force of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X125SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X125SFA replacement — usually within 7-8 hours.