This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X450LB, 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 SI125X450LB
The AirTAC SI125 Standard Cylinder SI125X450LB is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 450mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X450LB, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke450 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X450LB
- 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 SI125X450LB
The AirTAC SI125X450LB is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 450mm stroke. It delivers 6136N push and 5734N pull at 0.5MPa via a G1/2 port. The direct replacement is the SAI125X450LB, which shares identical mounting, force, and stroke specifications.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. For applications needing load holding, the SAI family adds SAIL and BSAI lock variants the SI lacked. This SKU lacks a magnet and cannot accept sensors.
Airtac SI125 Standard Cylinder SI125X450LB Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X450LB |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X450LB |
| Bore size | Ø125 mm |
| Stroke | 450 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 SAI125X450LB 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 SAI125X450LB 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 SI125X450LB
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×450 | 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 SI125X450LB Is Used
Heavy Press Clamping
Secures large metal castings in machining fixtures, utilizing the 6136N push force at 0.5MPa to hold components rigidly against cutting loads.
Pallet Dispenser Gate
Actuates heavy automated pallet flow gates over the 450mm stroke, requiring external guide rails to support the substantial mechanism weight.
Mold Ejection System
Drives large injection mold ejection plates, where the 5734N pull force at 0.5MPa reliably retracts heavy tooling cores without bounce.
Replacing the Airtac SI125 Standard Cylinder SI125X450LB with the SAI125X450LB
To replace the SI125X450LB, order the SAI125X450LB. Verify the ISO 15552 LB foot mounting interface, 125mm bore, 450mm stroke, G1/2 port, and M27x2 rod thread. Because this 450mm stroke is long, use external guides to prevent rod bending and side-load wear. If sizing alternatives, neighbouring bores change the force: a 100mm bore yields 3927N push, while a 160mm bore yields 10053N at 0.5MPa. Note that a plain cylinder drifts on air loss; for load holding, specify an external pilot check valve or the SAIL/BSAI lock variant. This no-magnet SKU cannot support legacy CS1-B/DS1-B switches.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X450LB
- ✓ 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 SI125X450LB FAQ
Yes, the SI125X450LB is discontinued. The direct replacement is the SAI125X450LB. It is dimensionally interchangeable per ISO 15552, matching the 125mm bore, 450mm stroke, LB foot mount, and G1/2 port, so it drops directly into existing fixtures.
This double-acting cylinder uses a G1/2 air port and generates 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N push at 0.9MPa, and a theoretical maximum of 1251kgf at 1.0MPa. It operates at 30-500mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X450LB
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X450LB replacement — usually within 7-8 hours.