This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX25S, 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 SI125BX25S
The AirTAC SI125 Standard Cylinder SI125BX25S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 25mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX25S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke25 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX25S
- 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 SI125BX25S
The AirTAC SI125BX25S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125mm bore and 25mm stroke. Built with a SUS304 stainless piston rod (-B) and a piston magnet (-S), it delivers 6136N push force at 0.5MPa through a G1/2 port. AirTAC replaced this EOL unit with the SAI125BX25S, a direct sharing the exact ISO 15552 mounting interface, stroke, force, and port size.
The SAI125BX25S upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life. The SAI family also introduces lock and valve variants the SI lacked, and this -S model accepts legacy CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125BX25S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX25S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX25S |
| Bore size | Ø125 mm |
| Stroke | 25 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 SAI125BX25S 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 SAI125BX25S 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 SI125BX25S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | 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 SI125 Standard Cylinder SI125BX25S Is Used
Heavy Press Clamping
Secures large steel plates in machining centers using the 6136N push force, while the SUS304 rod resens coolant corrosion.
Pallet Diverting
Short 25mm stroke actuates heavy-duty diverters on high-capacity packaging lines with rapid 30-500mm/s cycling.
Replacing the Airtac SI125 Standard Cylinder SI125BX25S with the SAI125BX25S
To replace the SI125BX25S, order the SAI125BX25S. Confirm the ISO 15552 mounting interface, the 125mm bore, 25mm stroke, G1/2 port (PT/G/NPT thread options), and your mounting accessory. The -B SUS304 rod and -S magnet carry over directly; the -S magnet works with CS1-B/DS1-B switches, while the SAI uses current AirTAC sensors. If you need more force, the 160mm bore offers 10053N push at 0.5MPa; if less is required, the 100mm bore provides 3927N. Note that a plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock or pilot check valve for load holding, or specify the SAIL or BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX25S
- ✓ 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 SI125BX25S FAQ
Yes, the SI125BX25S is discontinued. The direct replacement is the SAI125BX25S. It shares the identical ISO 15552 mounting interface, 125mm bore, 25mm stroke, force, and G1/2 port, fitting existing fixtures perfectly while upgrading the piston seal.
It features a G1/2 port. Force output is 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical max of 1251kgf at 1.0MPa. Operating speed is 30-500mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX25S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX25S replacement — usually within 7-8 hours.