This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX135S, 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 SI125BX135S
The AirTAC SI125 Standard Cylinder SI125BX135S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 135mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX135S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke135 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX135S
- 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 SI125BX135S
The AirTAC SI125BX135S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 135 mm stroke. It delivers 6136 N push force at 0.5 MPa through a G1/2 port. The direct replacement is the SAI125BX135S, sharing the same interface, stroke, force, and mounting fixtures.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. This -B variant uses a SUS304 stainless rod for corrosion resistance, and the -S magnet works with legacy CS1-B/DS1-B sensors. The SAI family also adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125BX135S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX135S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX135S |
| Bore size | Ø125 mm |
| Stroke | 135 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 SAI125BX135S 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 SAI125BX135S 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 SI125BX135S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×135 | 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 SI125BX135S Is Used
Heavy Pressing
Applies the 6136 N push force at 0.5 MPa for heavy-duty stamping, forming, and press-fit assembly operations.
Pallet Diverting
Handles high-load diverting and stopping of large pallets on conveyor lines using the robust 32 mm SUS304 rod.
Replacing the Airtac SI125 Standard Cylinder SI125BX135S with the SAI125BX135S
To replace the SI125BX135S, order the SAI125BX135S. Confirm the ISO 15552 mounting interface, 135 mm stroke, G1/2 port (PT/G/NPT thread), and mounting accessory. The SAI is a direct dimensionally interchangeable per ISO 15552. If downsizing, a 100 mm bore yields 3927 N push at 0.5 MPa; if upsizing, a 160 mm bore gives 10053 N. This -B model specifies a SUS304 stainless rod, and -S means a magnet is present for CS1-B/DS1-B switches. A plain cylinder drifts on air loss as the cushion only decelerates; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 135 mm stroke, side-load and rod-bending risks are low, but ensure proper guide alignment.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX135S
- ✓ 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 SI125BX135S FAQ
Yes, the SI125BX135S is discontinued. The direct replacement is the SAI125BX135S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 135 mm stroke, G1/2 port, and mounting interface, but features an upgraded piston seal.
The bore is 125 mm with a G1/2 air port and M27x2 rod thread. 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. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX135S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX135S replacement — usually within 7-8 hours.