This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X250FA, 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 SI125X250FA
The AirTAC SI125 Standard Cylinder SI125X250FA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 250mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X250FA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke250 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X250FA
- 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 SI125X250FA
The AirTAC SI125X250FA is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 250 mm stroke. Delivering 6136 N push force at 0.5 MPa via a G1/2 port, it is replaced by the SAI125X250FA. This direct successor shares the exact FA flange mounting, M27x2 rod thread, and 40 mm cushions.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. It also expands options with SAIL, SAIF, and BSAI variants. Note this non-magnet SKU cannot take a sensor.
Airtac SI125 Standard Cylinder SI125X250FA Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X250FA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X250FA |
| Bore size | Ø125 mm |
| Stroke | 250 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 SAI125X250FA 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 SAI125X250FA 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 SI125X250FA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×250 | 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 SI125X250FA Is Used
Heavy Press Operations
Ideal for driving large forming presses and stamping stations where the 6136 N push force at 0.5 MPa is required to shape thick materials.
Pallet Lift Gates
Provides the robust vertical lifting power needed for heavy-duty pallet gates and loading dock articulation, safely moving loads up to 313 kg.
Mold Clamping Fixtures
Secures large injection molds and heavy industrial fixtures using the FA flange mount, ensuring rigid holding during high-force manufacturing cycles.
Replacing the Airtac SI125 Standard Cylinder SI125X250FA with the SAI125X250FA
To replace the SI125X250FA, order the SAI125X250FA. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 250 mm stroke, FA flange, G1/2 port, and 40 mm cushions. If you need less force, step down to a 100 mm bore (3927 N push @0.5 MPa); for more power, a 160 mm bore yields 10053 N. This plain cylinder lacks a magnet and cannot accept a CS1-B/DS1-B sensor. Because air cushions only decelerate, use an external rod lock or pilot check valve for load holding, or specify an SAIL/BSAI lock variant. Since the 250 mm stroke is below 300 mm, side-load risks are minimal, but standard guide considerations apply.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X250FA
- ✓ 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 SI125X250FA FAQ
Yes, the SI125X250FA is discontinued. The direct replacement is the SAI125X250FA, which shares the same ISO 15552 mounting interface, 125 mm bore, 250 mm stroke, G1/2 port, and FA flange.
This double-acting cylinder features a G1/2 port and delivers a push force of 6136 N and pull of 5734 N at 0.5 MPa. At 0.7 MPa push is 8590 N, at 0.9 MPa it is 11045 N, and the theoretical max is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X250FA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X250FA replacement — usually within 7-8 hours.