This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX450S, 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 SI125BX450S
The AirTAC SI125 Standard Cylinder SI125BX450S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 450mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX450S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke450 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX450S
- 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 SI125BX450S
The AirTAC SI125BX450S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore, 450 mm stroke, and a SUS304 stainless steel piston rod. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125BX450S, which matches the ISO 15552 mounting interface, bore, stroke, force, G1/2 port, and accessories.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The original SI utilized CS1-B/DS1-B legacy sensors, while the SAI family supports current AirTAC switches and adds SAIL lock, SAIF valve, and BSAI clamp-lock variants.
Airtac SI125 Standard Cylinder SI125BX450S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX450S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX450S |
| Bore size | Ø125 mm |
| Stroke | 450 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 SAI125BX450S 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 SAI125BX450S 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 SI125BX450S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×450 | 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 SI125BX450S Is Used
Pallet Positioning Gate
Actuates large-scale 450 mm stroke diversion gates in high-throughput distribution centers, relying on the SUS304 rod for washdown corrosion resistance.
Mold Clamping Fixture
Secures heavy industrial molds using 11045 N push force at 0.9 MPa, requiring external guides to manage the side-load risks of the long stroke.
Replacing the Airtac SI125 Standard Cylinder SI125BX450S with the SAI125BX450S
To replace the SI125BX450S, order the SAI125BX450S, confirming the ISO 15552 interface, 450 mm stroke, G1/2 port, and SUS304 rod. If downsizing, a 100 mm bore yields 3927 N push at 0.5 MPa; if upsizing, a 160 mm bore provides 10053 N. Note that a plain cylinder drifts without live air, as the 40 mm adjustable cushion only decelerates the load. For load holding, specify an external pilot check valve or the SAIL/BSAI lock variant. Because the 450 mm stroke exceeds 300 mm, use external guides to prevent rod bending and side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX450S
- ✓ 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 SI125BX450S FAQ
Yes, the SI125BX450S is discontinued. The direct replacement is the SAI125BX450S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 450 mm stroke, output force, G1/2 port, and mounting interface.
This double-acting cylinder has a G1/2 air port. It generates 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 maximum of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX450S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX450S replacement — usually within 7-8 hours.