Rigid Conduit Reducer Coupling, Large End Trade Size 4 Inch, Small End Trade Size 3 Inch, Material Zinc Electroplated Malleable Iron, Size 5-3/8 Inch Dia x 3-3/16 Inch L, Enclosure Class I Div 1 2 Group A B C D, Class II Div 1 2 Group E F G, Class III, Approval CSA C22.2, Applicable Standard NEC 500 to 503/505, Constructional Feature Dust Ignitionproof, Explosion-Proof, Used On Threaded IMC/Rigid Metal Conduit