This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX125SN, 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 SI50BX125SN
The AirTAC SI50 Standard Cylinder SI50BX125SN 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 SAI50BX125SN, 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 → SAI50BX125SN
- 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 SI50BX125SN
The AirTAC SI50BX125SN is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 125mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50BX125SN, matching the exact interface, bore, stroke, force and mounting. This B-configured unit features a SUS304 stainless steel rod for corrosion resistance, an NBR seal (-20 to +70C), and a piston magnet for CS1-B/DS1-B legacy sensors.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL, SAIF and BSAI variants the SI lacked.
Airtac SI50 Standard Cylinder SI50BX125SN Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX125SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX125SN |
| 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 SAI50BX125SN 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 SAI50BX125SN 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 SI50BX125SN
| 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 SI50BX125SN Is Used
Stainless Rod Diverter
Ideal for diverting light packages on a washdown conveyor line, utilizing the SUS304 rod for corrosion resistance and 982N push force to actuate routing gates.
Vertical Lift Stopper
Serves as a vertical lift stopper for loads up to 50kg, safely halting pallets in a distribution hub using the 125mm stroke and integrated magnet for position confirmation.
Clamp Actuator
Provides reliable clamping force on small machined parts, where the 825N pull force at 0.5MPa securely holds components without deforming them.
Replacing the Airtac SI50 Standard Cylinder SI50BX125SN with the SAI50BX125SN
To replace the SI50BX125SN, order the SAI50BX125SN. Confirm the ISO 15552 mounting interface, 50mm bore, 125mm stroke, G1/4 port (PT/G/NPT thread), and mounting accessory. The -S magnet enables current AirTAC switches, and the -B specifies the SUS304 rod. If sizing up, the 63mm bore yields 1559N at 0.5MPa; if sizing down, the 40mm bore yields 628N. 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 variant. At 125mm stroke, side-load and rod-bending risks are minimal, but always guide the load.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX125SN
- ✓ 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 SI50BX125SN FAQ
Yes, the SI50BX125SN is discontinued. The direct replacement is the SAI50BX125SN. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 125mm stroke, 982N force, G1/4 port, and mounting interface.
This double-acting cylinder features a G1/4 air port. The thrust ratings are: 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical maximum of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX125SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX125SN replacement — usually within 7-8 hours.