This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX125S, 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 SI125BX125S
The AirTAC SI125 Standard Cylinder SI125BX125S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 125mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX125S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke125 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX125S
- 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 SI125BX125S
The AirTAC SI125BX125S is a discontinued double-acting ISO 15552 profile cylinder featuring a SUS304 stainless steel piston rod and a built-in magnet. Generating 6136 N push force at 0.5 MPa, it is replaced by the SAI125BX125S direct cylinder. This successor shares the exact G1/2 port, 125 mm bore, and 125 mm stroke, dropping straight into existing fixtures.
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 lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125BX125S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX125S |
| Bore size | Ø125 mm |
| Stroke | 125 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 SAI125BX125S 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 SAI125BX125S 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 SI125BX125S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | 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 SI125 Standard Cylinder SI125BX125S Is Used
Heavy Stamping Press
Drives large heavy-duty stamping dies requiring high thrust, utilizing the 6136 N push force at 0.5 MPa to form thick metal components reliably.
Automated Clamp Fixture
Secures large fabricated steel frames for welding, using the robust 32 mm SUS304 rod to resist side loads and environmental corrosion.
Replacing the Airtac SI125 Standard Cylinder SI125BX125S with the SAI125BX125S
To replace the SI125BX125S, order the SAI125BX125S. It matches the ISO 15552 mounting interface, 125 mm stroke, G1/2 port, and M27x2 rod thread. Confirm your mounting accessory (like TC trunnion or LB foot) and keep the -S magnet for position sensing. The SUS304 rod provides corrosion resistance over the standard carbon steel option. If you need more force, the 160 mm bore offers 10053 N at 0.5 MPa; if less is required, the 100 mm bore provides 3927 N. A plain cylinder drifts on air loss since the 40 mm cushion only decelerates, so use an external rod lock or pilot check valve for load holding. The SAIL or BSAI lock variants are ideal if you need integrated holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX125S
- ✓ 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 SI125BX125S FAQ
Yes, the SI125BX125S is discontinued. The direct replacement is the SAI125BX125S. It shares the same ISO 15552 mounting interface, 125 mm bore, 125 mm stroke, G1/2 port, and output force, fitting existing fixtures perfectly.
The 125 mm bore delivers 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical max of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX125S replacement — usually within 7-8 hours.