This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX300STC, 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 SI125BX300STC
The AirTAC SI125 Standard Cylinder SI125BX300STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 300mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX300STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke300 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX300STC
- 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 SI125BX300STC
The AirTAC SI125BX300STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 300 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125BX300STC, matching the bore, stroke, force, port and TC trunnion mounting interface.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. This -B variant uses a SUS304 stainless rod, and the -S magnet works with legacy CS1-B/DS1-B sensors. Note the 300 mm stroke requires external guides to prevent rod bending.
Airtac SI125 Standard Cylinder SI125BX300STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX300STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX300STC |
| Bore size | Ø125 mm |
| Stroke | 300 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 SAI125BX300STC 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 SAI125BX300STC 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 SI125BX300STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×300 | 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 SI125BX300STC Is Used
Heavy Stamping Press
Drives large heavy-duty stamping dies requiring 6136 N push force at 0.5 MPa with robust TC trunnion mounting.
Pallet Lift Station
Lifts loaded pallets vertically; the 300 mm stroke moves loads safely up to the 313 kg vertical-lift threshold.
Automated Assembly Fixture
Clamps large fabricated components securely during machining using the corrosion-resistant SUS304 rod.
Replacing the Airtac SI125 Standard Cylinder SI125BX300STC with the SAI125BX300STC
To replace the SI125BX300STC, order the SAI125BX300STC. Verify the ISO 15552 TC trunnion mount, 125 mm bore, 300 mm stroke, G1/2 port, SUS304 rod (-B) and magnet (-S). At 0.5 MPa it yields 6136 N push and 5734 N pull; neighbouring bores are 100 mm (3927 N) and 160 mm (10053 N). For the 300 mm stroke, add external guides to manage side-load and rod-bending risks. A plain cylinder drifts on air loss; for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX300STC
- ✓ 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 SI125BX300STC FAQ
Yes, the SI125BX300STC is discontinued. The direct replacement is the SAI125BX300STC. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 300 mm stroke, G1/2 port, TC mount and force ratings.
It features a G1/2 port. The force 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 max of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX300STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125BX300STC replacement — usually within 7-8 hours.