I recently installed a Moesgo Wi-Fi enabled switch, only to find that the new switch's thick, elongated back just didn't fit in my cluttered electrical box. Too bad. This is a problem with many electronic switches, including dimmer switches and GFCIs. The flat surface box extension turned out to be the PERFECT solution to my problem. It is very solidly built and fits perfectly. One of the very nice things is that the correct size (extended) screws are included in the kit.