Hose Thru Vents are designed for cabin or bilge ventilation. Constructed of UV resistant injection molded ABS. For use with 3? or 4? exhaust hose. Installs with four #8 FH fasteners (not included). Avoid contact with acetone or strong solvents. A 3-9/16" B 3" C 4-5/16" Hose 4" Color White