Can be cut to fit airpurifiers, Range hoods and furnace filters This package includes 18 cut-to-fit carbon activated pre-filter pads for Furnace Floor Register Vent fo Size 4” x 12” each They can be used for an extended period of time without affecting regular ventilation, maintaining air circulation, and keeping your home clean Reduces Household Odors From Cooking, Cleaning And Pets Can be cut to fit airpurifiers, Range hoods and furnace filters