Al Union, Thread Gender Male to Female, Trade Size 2 1/2 in, Ends – Hazardous Fittings 2 1/2 in FNPT x 2 1/2 in MNPT, Overall Length 4 1/16 in, Outside Diameter 4 in, Overall Width 3 15/16 in, Weight 1.36 lb, Aluminum, Finish Unfinished, Hazardous Location Rating Class I, Divisions 1 and 2, Groups A, B, C, D, Class II, Divisions 1 and 2, Groups E, F, G, Class III, Divisions 1 and 2, UNF, For Use With IMC, Rigid Conduit, Threaded Conduit, Conduit Fitting Type Union