Decora / Leviton Insert (blank)

thingiverse

This blank Decora wall plate is hollowed out on the back, making its face only 3mm thick. It's designed for low-voltage signal and data connectors like Ethernet, HDMI video, and audio. Connectors can be recessed by 1.5mm on the front to give a professional appearance. The insert also features wide internal mounting holes so it can be attached securely to a standard junction box that may not be perfectly upright.