Air King Deluxe Combination Heater AK093 The Deluxe Round Combination Heater Series is the solution to rooms that need extra warmth HVI2100 Certified: 70 CFM @ 3.5 Sones exhaust 4" duct collar with backdraft damper prevents drafts from entering back into the room Wall switches and wall plate included with unit Effective ventilation for rooms 65 to 85 sq. ft.