This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX300S, 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 SI125BX300S
The AirTAC SI125 Standard Cylinder SI125BX300S 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 SAI125BX300S, 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 → SAI125BX300S
- 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 SI125BX300S
The AirTAC SI125BX300S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 300 mm stroke. Featuring a SUS304 stainless steel piston rod and a built-in magnet for legacy CS1-B/DS1-B switches, it delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125BX300S, matching the G1/2 port, M27x2 thread, and ISO 15552 mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI lock variants. Note that standard cylinders drift without live air; use SAIL or BSAI for load holding.
Airtac SI125 Standard Cylinder SI125BX300S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX300S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX300S |
| 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 SAI125BX300S 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 SAI125BX300S 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 SI125BX300S
| 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 SI125BX300S Is Used
Heavy Stamping Press
Drives large heavy-duty stamping presses requiring high thrust, utilizing the 6136 N push force at 0.5 MPa with SUS304 rod durability.
Automated Clamp Fixture
Secures large automotive components during machining, relying on the 125 mm bore's 5734 N pull force and ISO 15552 mounting rigidity.
Replacing the Airtac SI125 Standard Cylinder SI125BX300S with the SAI125BX300S
To replace the discontinued SI125BX300S, order the SAI125BX300S. Verify your ISO 15552 mounting interface (LB, FA, TC, etc.), the G1/2 port, and the -S magnet for current AirTAC switches. The -B rod is SUS304 stainless steel. At 0.5 MPa it yields 6136 N push and 5734 N pull; if undersizing, a 100 mm bore gives 3927 N. For the 300 mm stroke, use external guides to prevent rod bending and side-load wear. The cushion only decelerates; it does not hold load. For secure holding on air loss, specify the SAIL or BSAI lock variant, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX300S
- ✓ 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 SI125BX300S FAQ
Yes, the SI125BX300S is discontinued. The direct replacement is the SAI125BX300S. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 300 mm stroke, G1/2 port, and mounting interface.
It features a G1/2 port. The force ratings are: 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 SAI125BX300S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX300S replacement — usually within 7-8 hours.