Lightweight, Non-corrosive and Non-conductive, rigid, Non-metallic wiring box combines features of hard shell thermoset box and thermoplastic PVC style box. Molded of specially formulated, strong thermoplastic material, will not crack or break, even in extreme environments. Resists flexing and holds shape even under the worst conditions. Provides large wire fill capacity and comes with molded-in nailing flanges and molded-in swing clamps to make installation faster. Designed to nest inside one another to take up less shelf space and are easier to transport to job sites. 3.85 in x 4.17 in. UL listed.