This AC WORKS brand extension cord is heavy-duty with durable construction. The cable is SOOW, 10/4, 30 Amp copper with a 600 Volt rubber jacket. The jacket will stay flexible in extremely cold temperatures. This cord is popular for use with transfer switches, inlet boxes, generators, for Industrial use, and construction. This L14-30 extension cord comes in lengths of 10ft, 25ft, 50ft, 75ft, and 100ft.