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 4 in cluded adjustable hanging brackets. Motors are suitable for continuousoperation, 6-Inch 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: 12-7/8 in W x 12-3/4 in D x 9-7/8 in H.