This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX300, 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 SI125BX300
The AirTAC SI125 Standard Cylinder SI125BX300 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 300mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX300, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke300 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX300
- 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 SI125BX300
The AirTAC SI125BX300 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 300 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125BX300, matching the interface, force, G1/2 port, and stroke.
This unit features a SUS304 stainless piston rod. It lacks a magnet, so it cannot take a sensor. The SAI upgrade uses two Y-shaped piston seals for low start-up pressure.
Airtac SI125 Standard Cylinder SI125BX300 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX300 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX300 |
| Bore size | Ø125 mm |
| Stroke | 300 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 SAI125BX300 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 SAI125BX300 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 SI125BX300
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×300 | 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 SI125BX300 Is Used
Heavy Stamp Pressing
Drives large stamping dies requiring substantial thrust, utilising the 6136 N push force at 0.5 MPa to form thick metal components reliably.
Large Clamp Fixtures
Secures oversized workpieces in machining centers where the SUS304 rod prevents corrosion from cutting fluids.
Replacing the Airtac SI125 Standard Cylinder SI125BX300 with the SAI125BX300
To replace this SI with the SAI125BX300, verify the ISO 15552 mounting interface, 300 mm stroke, and G1/2 port. This SKU has no magnet and cannot accept a sensor; order a -S version if sensing is needed. The SUS304 rod suits corrosive settings. At 300 mm stroke, use external guides to prevent rod bending. For load holding on air loss, use an external rod lock or pilot check valve, as cushions only decelerate. Neighbouring bores: 100 mm gives 3927 N push; 160 mm gives 10053 N push at 0.5 MPa.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX300
- ✓ 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 SI125BX300 FAQ
Yes, the SI125BX300 is discontinued. The direct replacement is the SAI125BX300, a true ISO 15552 profile cylinder that matches the bore, stroke, force, G1/2 port, and mounting interface for an easy fixture swap.
It has a G1/2 port. Force output is 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. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX300
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX300 replacement — usually within 7-8 hours.