This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X400FTC, 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 SI125X400FTC
The AirTAC SI125 Standard Cylinder SI125X400FTC 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 SAI125X400FTC, 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 → SAI125X400FTC
- 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 SI125X400FTC
The AirTAC SI125X400FTC is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 400mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. AirTAC replaced this legacy unit with the SAI125X400FTC, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, output force, and FTC trunnion mount.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. This non-magnet SKU cannot accept a sensor, unlike the CS1-B/DS1-B switches used on -S models.
Airtac SI125 Standard Cylinder SI125X400FTC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X400FTC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X400FTC |
| 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 SAI125X400FTC 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 SAI125X400FTC 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 SI125X400FTC
| 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 SI125X400FTC Is Used
Heavy Stamping Press
Drives large heavy-duty stamping actuators where the 6136 N push force at 0.5 MPa easily overcomes thick material resistance.
Bulk Material Diversion
Actuates heavy lane diverters on high-capacity conveyor lines, utilizing the 400mm stroke to fully redirect wide product flows.
Replacing the Airtac SI125 Standard Cylinder SI125X400FTC with the SAI125X400FTC
To replace this SI cylinder, order the SAI125X400FTC. Verify the ISO 15552 FTC trunnion mount, 125mm bore, 400mm stroke, and G1/2 port (available in PT, G, or NPT). Size both ways: neighboring 100mm bore yields 3927 N push at 0.5 MPa, while 160mm yields 10053 N. Note this plain cylinder drifts without live air; the 40mm cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. At 400mm stroke, prevent rod bending by guiding the load externally. Rod options include carbon steel, SUS420J2 (A), or SUS304 (B); Viton H seals allow 0-150 C operation.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X400FTC
- ✓ 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 SI125X400FTC FAQ
Yes, the AirTAC SI125X400FTC is discontinued. The direct replacement is the SAI125X400FTC. It is dimensionally interchangeable per ISO 15552, matching the 125mm bore, 400mm stroke, G1/2 port, force, and FTC trunnion mounting interface.
This double-acting cylinder features a G1/2 air port and a 32mm rod. It generates 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N at 0.9 MPa, and a theoretical maximum of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X400FTC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X400FTC replacement — usually within 7-8 hours.