This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAIJ125X400-75, 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.

The AirTAC SIJ125 Double Rod Adjustable Cylinder SIJ125X400-75 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 SAIJ125X400-75, which matches its ISO interface, bore, stroke, force and mounting.
The AirTAC SIJ125X400-75 is a discontinued double-acting double-rod ISO 15552 adjustable-stroke cylinder with a 125 mm bore and 400 mm nominal stroke. An external stop screw lets you trim the extend stroke by up to 75 mm on-site, yielding a usable extend range of 325-400 mm. The stop sets the end position; it is not a load lock. Operating speed is 30-500 mm/s.
As SIJ is end-of-life, the direct replacement is the SAIJ125X400-75, preserving the ISO 15552 mounting interface, force, and adjust window. The SAIJ upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life. This non-magnetic SKU cannot take a switch; for load holding on air loss, use an external rod lock or SAIL/BSAI variant.
| Model | Airtac SIJ125 Double Rod Adjustable Cylinder SIJ125X400-75 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAIJ125X400-75 |
| 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 SAIJ125X400-75 carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAIJ125X400-75 produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
| 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).
Dialing in exact insertion depth on a 325-400 mm extend, allowing operators to trim the final 75 mm on-site without machining custom spacers.
Adjusting a divert arm end position to handle changing package sizes on a packaging line, using the external stop to set the precise extend limit.
Setting a repeatable mechanical end position for heavy pallet handling where the nominal 400 mm stroke must be shortened to clear existing fixtures.
To replace the discontinued SIJ125X400-75, order the direct replacement SAIJ125X400-75, which retains the G1/2 port, 75 mm adjust window, and ISO 15552 mounting. Choose the 75 mm adjust window if your extend stroke needs on-site tuning between 325-400 mm. Mounting options include FA, LB, and TC. Because this SKU lacks the -S suffix, it cannot accept a magnetic switch. With a 400 mm stroke, mind side-load and rod-bending forces; use external guides to prevent premature wear.
Replacement checklist
Yes, the SIJ125X400-75 is discontinued. The direct replacement is the SAIJ125X400-75. It shares the same ISO 15552 interface, 125 mm bore, 400 mm stroke, 75 mm adjust window, and G1/2 port. The SAIJ family also adds an upgraded two Y-shaped one-way piston seal for lower start-up pressure and longer life.
The external stop screw provides a 75 mm adjust window, allowing the extend stroke to be trimmed from 400 mm down to 325 mm. The stop sets end position but is not a load lock.
Send us the quantity and destination. We confirm price, stock and lead time on the SAIJ125X400-75 replacement — usually within 7-8 hours.