The CT20 is an electronic tool for electricians, alarm, cable installers and others who routinely need to check circuits for continuity and also identify cables and wires. It allows a single user to quickly identify and label two wires even when the wire ends are located in different rooms. It can accommodate test wire lengths up to 10 000 ft (3000 m), 26 ga minimum. The CT20's remote continuity mode allows the user to check continuity and to identify two or more cables/wires simultaneously.