This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX210S, 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 SI125BX210S
The AirTAC SI125 Standard Cylinder SI125BX210S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 210mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX210S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke210 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX210S
- 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 SI125BX210S
The AirTAC SI125BX210S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 210 mm stroke, and a SUS304 stainless piston rod. Delivering 6136 N push force at 0.5 MPa, it is replaced by the SAI125BX210S. This direct successor shares the exact ISO 15552 mounting interface, G1/2 port, and M27x2 rod thread, fitting existing fixtures perfectly.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125BX210S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX210S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX210S |
| Bore size | Ø125 mm |
| Stroke | 210 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 SAI125BX210S 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 SAI125BX210S 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 SI125BX210S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×210 | 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 SI125BX210S Is Used
Heavy Press Operations
Ideal for high-force pressing and stamping tasks requiring the 6136 N thrust at 0.5 MPa, utilizing the robust 125 mm bore and adjustable 40 mm cushions.
Large Clamp Fixtures
Generates secure 5734 N pull force at 0.5 MPa for holding heavy workpieces in machining centers, with the G1/2 port ensuring adequate flow.
Replacing the Airtac SI125 Standard Cylinder SI125BX210S with the SAI125BX210S
To replace the SI125BX210S, order the SAI125BX210S. Confirm the ISO 15552 mounting accessory (LB, FA, CA, TC), the G1/2 port, and the -S magnet for current AirTAC switches. The B suffix denotes the SUS304 rod; keep it for wet environments. Sizing both ways: a 100 mm bore gives 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variant. At 210 mm stroke, side-load is moderate, but always guide the load to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX210S
- ✓ 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 SI125BX210S FAQ
Yes, the SI125BX210S is discontinued. The direct replacement is the SAI125BX210S. It is dimensionally interchangeable per ISO 15552, matching the bore, stroke, force, G1/2 port, and mounting interface.
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 SAI125BX210S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX210S replacement — usually within 7-8 hours.