4" Type B Gas Vent Hold-Down Plate, Type Bw Gas Vent When Installed On Wall Furnace Using 408 Pws Hold Down Plate And 40 Cp Plate Spacers And 40 Fs Firestop Spacers, Type B Gas Vent When Installed With 1" Minimum Clearance To Combustibles Or When Installed Between 2 X 4 Wall Studs Using 40 Fs Firestop Spacers, Dims:11/2"H X 3 "W X 95/8"L, Weight:2 Oz, Bulk, Made In Mexico.