Dundas Jafine ProVent exhaust hoods feature a 3 louver damper system that helps to prevent cold air backdraft, snow or rain from entering the home. The louvers are cammed to allow for easy pivoting and to help prevent sticking. Additional features include a recessed caulk line to assist in a clean caulking application and a snap on pipe to cap assembly that eliminates the need for lint trapping staples.