This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X125S, 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 SI50X125S
The AirTAC SI50 Standard Cylinder SI50X125S 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 SAI50X125S, 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 → SAI50X125S
- 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 SI50X125S
The AirTAC SI50X125S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 125 mm stroke. It delivers 982 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI50X125S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, stroke, output force, and port size.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This -S model has a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI50 Standard Cylinder SI50X125S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X125S |
| 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 SAI50X125S 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 SAI50X125S 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 SI50X125S
| 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 SI50X125S Is Used
Package Diversion
Actuates routing gates on packaging lines where 982 N push force easily deflects standard cartons.
Clamp Actuation
Secures medium workpieces in machining fixtures, providing a safe 589 N holding margin at 0.5 MPa.
Vertical Lift Stops
Raises 50 kg pallet stops in material handling hubs, utilizing the 125 mm stroke for precise positioning.
Replacing the Airtac SI50 Standard Cylinder SI50X125S with the SAI50X125S
To replace the SI50X125S, order the SAI50X125S. Confirm your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port thread (PT, G, or NPT), and the M16x1.5 rod end. The -S suffix means a magnet is present for CS1-B/DS1-B switches; a no-S SKU cannot take a sensor. If you need more force, the neighbouring 63 mm bore yields 1559 N push at 0.5 MPa; if less is acceptable, the 40 mm bore provides 628 N. Note that 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 variant. At 125 mm stroke, rod bending is minimal, but always guide the load to prevent side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X125S
- ✓ 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 SI50X125S FAQ
Yes, the SI50X125S is discontinued. The direct replacement is the SAI50X125S. It shares the identical ISO 15552 mounting interface, 50 mm bore, 125 mm stroke, force, and G1/4 port, fitting existing fixtures perfectly.
This double-acting cylinder features a G1/4 air port. It delivers 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and 1767 N push at 0.9 MPa. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X125S replacement — usually within 7-8 hours.