This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X270S, 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 SI125X270S
The AirTAC SI125 Standard Cylinder SI125X270S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 270mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X270S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke270 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X270S
- 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 SI125X270S
The AirTAC SI125X270S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore, 270 mm stroke, and a built-in piston magnet for CS1-B/DS1-B switches. It delivers 6136 N push force at 0.5 MPa through a G1/2 port. AirTAC replaced this legacy unit with the SAI125X270S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, stroke, output force, and port size.
The SAI upgrade introduces a refined piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. For load holding, note that a plain cylinder drifts on air loss—the cushion only decelerates—so consider the SAIL lock or BSAI clamp-lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125X270S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X270S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X270S |
| Bore size | Ø125 mm |
| Stroke | 270 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 SAI125X270S 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 SAI125X270S 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 SI125X270S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×270 | 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 SI125X270S Is Used
Heavy-Duty Pressing
Drives large stamping and forming fixtures requiring substantial thrust, delivering up to 8590 N at 0.7 MPa to seat heavy components.
Pallet Positioning
Indexes loaded pallets on conveyor lines, utilizing the 270 mm stroke to push or align heavy goods securely into packaging stations.
Automated Clamping
Secures large workpieces during machining operations, providing reliable holding power and smooth deceleration via adjustable 40 mm cushions.
Replacing the Airtac SI125 Standard Cylinder SI125X270S with the SAI125X270S
To replace the SI125X270S, order the SAI125X270S. Verify the ISO 15552 mounting interface, 125 mm bore, 270 mm stroke, G1/2 port (PT/G/NPT thread options), and the -S magnet for CS1-B/DS1-B sensors. Sizing both ways: the neighboring 100 mm bore yields 3927 N push at 0.5 MPa, while the 160 mm bore provides 10053 N. At 0.7 MPa this 125 mm unit pushes 8590 N. A plain cylinder does not hold load without live air; the cushion only decelerates. For held loads, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. For any stroke >= 300 mm, ensure external guide rails to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X270S
- ✓ 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 SI125X270S FAQ
Yes, the SI125X270S is discontinued. The direct replacement is the SAI125X270S. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 270 mm stroke, output force, G1/2 port, and mounting accessories, so it drops directly into existing fixtures.
This double-acting cylinder uses a G1/2 air port. It delivers 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 force of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X270S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X270S replacement — usually within 7-8 hours.