These 3d printed frames fit between the wall and the Aqara smart switch and allows for installation of the EU sized switch on a standard SA 2×4 light box. The 3d printed plate is attached to the 2×4 wall box with 2x screws. Thereafter the wires are connected ot the switch, and the switch inserted into the 3d plate. (Note that some force is required to press the switch into the 3d frame. This is by design and intended to eliminate the need for additional screws.) To assist with the final fitment, it is recommended that the switch be inserted in to the frame a few times, before commencing with actual installation.
For an alternative solution, also have a look at our laser cut Adaptor Plate for Aqara H1 Smart switch.