This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX650S, 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 SI125BX650S
The AirTAC SI125 Standard Cylinder SI125BX650S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 650mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX650S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke650 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX650S
- 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 SI125BX650S
The AirTAC SI125BX650S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 650 mm stroke. It delivers 6136 N push force at 0.5 MPa, features a SUS304 stainless piston rod (-B), a built-in magnet (-S), and a G1/2 air port. The direct replacement is the SAI125BX650S, which shares the exact ISO 15552 mounting interface, bore, stroke, output force, and porting.
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 and BSAI lock variants absent from the legacy SI line.
Airtac SI125 Standard Cylinder SI125BX650S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX650S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX650S |
| Bore size | Ø125 mm |
| Stroke | 650 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 SAI125BX650S 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 SAI125BX650S 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 SI125BX650S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×650 | 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 SI125BX650S Is Used
Heavy Press Clamping
Applies the 8590 N push force at 0.7 MPa to secure large metal castings during machining operations.
Bulk Material Diversion
Drives heavy diverter gates across 650 mm of travel to route dense aggregates on processing lines.
Replacing the Airtac SI125 Standard Cylinder SI125BX650S with the SAI125BX650S
To replace the SI125BX650S, order the SAI125BX650S. Confirm the ISO 15552 mounting interface, the 650 mm stroke, the G1/2 port, and your mounting accessory (LB, FA, TC, etc.). The -S magnet enables CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches; the -B rod is SUS304 stainless. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. Note that a plain cylinder drifts without live air—the cushion only decelerates—so use an external rod lock or pilot check valve for load holding. Because the 650 mm stroke is long, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX650S
- ✓ 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 SI125BX650S FAQ
Yes, the SI125BX650S is discontinued. The direct replacement is the SAI125BX650S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 650 mm stroke, G1/2 port, and mounting interface.
At 0.5 MPa it provides 6136 N push and 5734 N pull force. At 0.7 MPa push is 8590 N, and at 0.9 MPa it is 11045 N. The theoretical max force is 1251 kgf at 1.0 MPa. It operates at 30-500 mm/s, uses a G1/2 port, and the -B option specifies a SUS304 stainless steel rod.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX650S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX650S replacement — usually within 7-8 hours.