Flush mounted with bracket, the UWZ48E unit fits into a 1.79" x 1.79" (45.5 x 45.5 mm) cutout. The thickness of the panel for flush mounting can be up to .35" (9 mm). The unit is secured in position by a plastic slip-on retaining bracket. The unit also fits square or round openings for 72 mm with optional 72 mm bezel.