Low profile grill almost disappears into ceiling and a motor with a large, quiet, centrifugal blower wheel. Provides lowest possible HVI certified sound rating. Install using the four included adjustable hanging brackets. Motors are suitable for continuous operation, 6 in round duct connector with a spring-loaded metal damper. For use over a tub or shower when installed on a GFCI circuit. Side access panel allows wiring fan from inside or outside the housing. Complies with ASHRAE 62.2 the minimum national standard, has three main components source control, local exhaust and whole house ventilation. Housing size of 12-7/8 x 12-3/4 x 9-7/8 in.