Sheet Metal Duct Adapter, Pressure Rating - Maximum Not Applicable, End 1 Non-Threaded Diameter 2 1/2 in, End 2 Non-Threaded Diameter 3 in, End 1 Thread Gender Not Applicable, End 2 Thread Gender Not Applicable, End 1 Thread Type Not Applicable, End 2 Thread Type Not Applicable, End 2 Thread Size Not Applicable, End 1 Thread Size Not Applicable, Product Type Duct Adapter, Resistance Properties , Water , Material Acetal, For Use With 2.5 in Loc-Line Systems