Heng's Industries Roof Vent 12 Volt 14" X 14" No Interior Garnish included Elixir Universal, Old Style Vent 17-71112-C Rough Cut-out Opening Dimensions (this is the hole you will need in your unit): 14 1/2" X 14 1/2" Exterior Mounting Flange Dimensions (sits on the top of your unit): 16 1/2" X 16 1/2" Does NOT include Garnish/Interior Trim Ring