This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX850S, 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 SI125BX850S
The AirTAC SI125 Standard Cylinder SI125BX850S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 850mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX850S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke850 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX850S
- 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 SI125BX850S
The AirTAC SI125BX850S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 850 mm stroke, and SUS304 stainless steel rod. Delivering 6136 N push force at 0.5 MPa, it is replaced by the SAI125BX850S. This direct successor shares the exact G1/2 port, M27x2 thread, and ISO 15552 mounting interface.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure. The SI -S magnet works with CS1-B/DS1-B sensors, while the SAIL lock and BSAI clamp-lock variants offer load holding the plain cylinder lacks.
Airtac SI125 Standard Cylinder SI125BX850S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX850S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX850S |
| Bore size | Ø125 mm |
| Stroke | 850 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 SAI125BX850S 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 SAI125BX850S 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 SI125BX850S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×850 | 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 SI125BX850S Is Used
Heavy Stamping
Drives large presses with 8590 N push at 0.7 MPa, using the SUS304 rod to resist corrosion in humid workshops.
Pallet Routing
Shifts heavy pallets over 850 mm, requiring external guides to prevent rod bending during lateral transfers.
Material Lowering
Lowers 313 kg loads vertically, relying on adjustable 40 mm cushions to decelerate without locking the load.
Replacing the Airtac SI125 Standard Cylinder SI125BX850S with the SAI125BX850S
To replace the SI125BX850S, order the SAI125BX850S, confirming the ISO 15552 interface, 850 mm stroke, G1/2 port, and SUS304 rod. If down-sizing, a 100 mm bore yields 3927 N push at 0.5 MPa; if up-sizing, a 160 mm bore yields 10053 N. At 850 mm, prevent rod bending by using external guides to absorb side loads. The standard cylinder drifts without air; for load holding, use the SAIL or BSAI lock variant, or an external pilot check valve. The -S magnet pairs with CS1-B/DS1-B switches.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX850S
- ✓ 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 SI125BX850S FAQ
Yes, the SI125BX850S is discontinued. The direct replacement is the SAI125BX850S. It shares the same ISO 15552 mounting interface, 125 mm bore, 850 mm stroke, G1/2 port, and output force, fitting existing fixtures perfectly.
At 0.5 MPa it pushes 6136 N and pulls 5734 N. At 0.7 MPa it pushes 8590 N, and 11045 N at 0.9 MPa. The theoretical max is 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX850S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX850S replacement — usually within 7-8 hours.