This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX900, 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 SI125BX900
The AirTAC SI125 Standard Cylinder SI125BX900 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 900mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX900, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke900 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX900
- 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 SI125BX900
The AirTAC SI125BX900 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore, 900 mm stroke, and a SUS304 stainless steel piston rod. Delivering 6136 N push force at 0.5 MPa, it is replaced by the direct replacement SAI125BX900. This current-production upgrade shares the exact same G1/2 port, M27x2 thread, and mounting interface, fitting existing fixtures perfectly.
The SAI125BX900 upgrades the piston seal to two Y-shaped one-way elements for low start-up pressure and long life. Note this SKU lacks a magnet and cannot take a sensor. The SAI family also adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125BX900 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX900 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX900 |
| Bore size | Ø125 mm |
| Stroke | 900 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 SAI125BX900 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 SAI125BX900 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 SI125BX900
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×900 | 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 SI125BX900 Is Used
Heavy Material Lifts
Drives large vertical platform elevators and heavy pallet lifts requiring the full 6136 N push force at 0.5 MPa over an extended 900 mm travel.
Large Press Ejection
Ejects heavy formed parts from large stamping presses, utilising the 40 mm adjustable air cushions to decelerate the 125 mm bore at stroke ends.
Automated Warehousing
Actuates heavy-duty automated storage and retrieval system shuttles where the SUS304 stainless rod resists environmental corrosion.
Replacing the Airtac SI125 Standard Cylinder SI125BX900 with the SAI125BX900
To replace the SI125BX900, order the SAI125BX900. Confirm the ISO 15552 mounting interface, 900 mm stroke, G1/2 port, and SUS304 rod. Because this SKU has no -S magnet, it cannot accept a CS1-B/DS1-B sensor. At 0.5 MPa it yields 6136 N push and 5734 N pull; if undersized, the neighbouring 160 mm bore offers 10053 N. For the 900 mm stroke, use external guides to prevent rod-bending and side-load damage. The air cushion only decelerates; use an external rod lock or pilot check valve for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX900
- ✓ 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 SI125BX900 FAQ
Yes, the SI125BX900 is discontinued. The direct replacement is the SAI125BX900. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 900 mm stroke, G1/2 port, and mounting interface.
The G1/2 port bore delivers a push force of 6136 N and a pull force of 5734 N at 0.5 MPa. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX900
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX900 replacement — usually within 7-8 hours.