Box designed to comfortably fit WAGO terminals and cables together with the Shelly module. It is not intended for simultaneous connection of an addon - it does not fit vertically.
The box is intentionally ventilated, there are holes for screws prepared for wall installation, although free laying on the floor will also work. I recommend using M3x16 Allen screws (you do not need to use an insert - the model has a printed thread)

Ideally print on a layer of 0.16, nozzle 0.4.