The Fuji PXF4AEP2-FB1A1 is a self-tuning 1/16 DIN (48 x 48mm) compact temperature and process controller with a 50ms sampling speed. The self-tuning algorithm sets the PID gains automatically on the first heat-up, so you don't need an engineer with a step-response timer to commission it.
The 1/16 DIN (48 x 48mm) cutout is the standard panel-mount footprint — fits the same hole as every other 1/16 DIN controller on the market. No DIN rail; it's panel-mounted with the bracket and gasket. The compact depth leaves room behind the door for wiring and the SSR heatsink. If you're replacing an older Fuji PXR or PXG in the same cutout, the wiring base may differ — check the terminal assignment against your existing panel drawing before pulling wires.