This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX155, 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 SI125BX155
The AirTAC Airtac SI125 Standard Cylinder SI125BX155 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 155mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX155, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke155 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX155
- 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 SI125BX155
The AirTAC SI125BX155 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore and 155 mm stroke. Delivering 6136 N push force at 0.5 MPa, it is superseded by the direct replacement SAI125BX155. The SAI upgrade retains the exact ISO 15552 mounting interface, G1/2 port, and output force, while introducing an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life.
This specific SKU includes a SUS304 stainless steel piston rod for corrosion resistance. Because it lacks a magnet (-S), it cannot accept position sensors. Note that a standard cylinder drifts without live air; for held loads, consider the SAIL or BSAI lock variants.
Airtac SI125 Standard Cylinder SI125BX155 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX155 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX155 |
| Bore size | Ø125 mm |
| Stroke | 155 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 SAI125BX155 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 SAI125BX155 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 SI125BX155
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×155 | 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 SI125BX155 Is Used
Heavy Machinery Forming
Drives large forming dies and heavy presses requiring 6136 N push force at 0.5 MPa with robust 125 mm bore stability.
Automated Clamp Systems
Secures oversized components during machining, relying on the 155 mm stroke and ISO 15552 mounting for rigid fixture integration.
Replacing the Airtac SI125 Standard Cylinder SI125BX155 with the SAI125BX155
To replace the discontinued SI125BX155, order the SAI125BX155. Confirm the ISO 15552 mounting interface, 125 mm bore, 155 mm stroke, G1/2 port, and your specific mounting accessory. This SKU uses a SUS304 stainless steel rod (option B) and has no magnet, meaning it cannot support CS1-B or DS1-B sensors. If sensing is required, select an SAI model with the -S suffix. For sizing alternatives, neighbouring bores like 100 mm (3927 N push @0.5 MPa) or 160 mm (10053 N push @0.5 MPa) offer different force classes. Because this is a plain double-acting cylinder, the 40 mm adjustable air cushions only decelerate the piston near stroke end; they do not hold loads on air loss. For secure load holding, explore the SAIL air-released lock or BSAI clamp-lock variants, or use an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX155
- ✓ 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 SI125BX155 FAQ
Yes, the AirTAC SI125BX155 is discontinued. The direct replacement is the SAI125BX155. It shares the same ISO 15552 mounting interface, 125 mm bore, 155 mm stroke, output force, and G1/2 port, fitting directly into existing fixtures.
This 125 mm bore cylinder features a G1/2 port and a 32 mm piston rod. It 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 SAI125BX155
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX155 replacement — usually within 7-8 hours.