The ClearMirror shower mirror remains fog-free in your shower or steam room to make shaving and facials a breeze. Made of high-quality glass with a low-voltage heating pad adhered to the back. It installs directly into the wall to remain flush with the tile. You choose the most convenient location and height for the mirror. With a simple flip of a switch, the mirror automatically begins to heat, preventing the build up of fog for long lasting clear vision. Mirror measures 17 5/8" x 17 5/8". *The Shower ClearMirror is UL and CUL tested to CSA international standards. The low voltage insures that electrical shocking cannot take place. The standard power supply includes a 120-volt primary and a 24-volt secondary plug-in transformer.