Heater, exhaust fan and light combination. Installs in ceiling. Heater blower wheel is one piece metal and electronically balanced. Ventilation blower wheel is one-piece polymeric and electronically balanced. Ultra safe ceramic heating element bonded to large heat transfer surface allows heating at very low operating temperature. Self-regulating design provides 1350 W. Moonstone glass lens, installed in a flip down lens holder. 100 W incandescent capacity, type A lamp required, bulb not included. UL listed. HVI2100 certified. Duct collar 4 in round, zinc-plated metal collar adapter with aluminum back draft damper.