Sea-Dog hose thru-vent is designed for cabin or bilge ventilation. Constructed of injection-molded ABS, it is UV-resistant. Thru-vent is for use with 4" exhaust hose. Installs with four #8 FH fasteners (not included). Note: Avoid contact with acetone or strong solvents. 4-15/16"L x 4-15/16"W x 3"D.