Replacement Boat Parts 3" stainless steel clad domed vent Domed 316 stainless steel clad vent grill fits 3" hose Holds 3" blower hose with no clamps or fasteners! Looks great and provides 3.997 square inches of ventilation Requires a 3-1/4" hole. Overall dimensions: 3.5" diameter, 1.25" long tailpiece.