This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400FA, 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 SI125X400FA
The AirTAC SI125 Standard Cylinder SI125X400FA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X400FA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X400FA
- 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 SI125X400FA
The AirTAC SI125X400FA is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 400 mm stroke. It delivers 6136 N push and 5734 N pull at 0.5 MPa, utilizing a G1/2 port and M27x2 rod thread. The direct replacement is the SAI125X400FA, which maintains the same ISO 15552 mounting interface, bore, stroke, output force, and FA flange accessory.
The SAI upgrade features a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note this non-magnet SKU cannot accept a sensor. The SAI family also introduces SAIL and BSAI lock variants absent in the legacy line.
Airtac SI125 Standard Cylinder SI125X400FA Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400FA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400FA |
| Bore size | Ø125 mm |
| Stroke | 400 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 SAI125X400FA 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 SAI125X400FA 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 SI125X400FA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×400 | 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 SI125X400FA Is Used
Heavy Stamping Press
Drives large platens and stamping dies requiring up to 8590 N of push force at 0.7 MPa, utilizing the rigid FA flange mount to handle heavy industrial shock.
Bulk Material Diversion
Actuates large-scale sorting gates and heavy diverters on high-capacity packaging lines, benefiting from the 30-500 mm/s speed range and 40 mm cushions.
Replacing the Airtac SI125 Standard Cylinder SI125X400FA with the SAI125X400FA
To replace the SI125X400FA, order the SAI125X400FA. Verify the ISO 15552 FA flange interface, 400 mm stroke, and G1/2 port (available in PT, G, or NPT). Because this SKU lacks the -S magnet, it cannot support legacy CS1-B/DS1-B sensors; order a magnet-equipped SAI if position detection is needed. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. For the 400 mm stroke, use external guides to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400FA
- ✓ 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 SI125X400FA FAQ
Yes, the SI125X400FA is discontinued. The direct replacement is the SAI125X400FA. It is dimensionally interchangeable per the ISO 15552 mounting interface, retaining the same 125 mm bore, 400 mm stroke, G1/2 port, and FA flange.
This double-acting cylinder uses a G1/2 port. The thrust 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 maximum of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X400FA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400FA replacement — usually within 7-8 hours.