The IDEAL 61 957 Sure Trace circuit kit includes 1 TR 955 Transmitter, 1 RC 959 Receiver, 1 TL 956 Tracer Test Lead Set and 1 C 957 hard case. The TR 955 transmitter injects a powerful signal into the circuit which allows you to test energized circuits up to 600V AC/DC as well as test de energized circuits. It identifies breakers/fuses with Certain Circuit detection. It pinpoints opens and shorts and traces wires behind walls. It can be used on GFCI protected circuits and comes supplied with four AA batteries. The RC 959 receiver contains a super bright OLED display and can rotate in 90 degree increments. The receiver displays signal strength in 0 99 increments and has four modes of sensitivity. The numeric value and audible signal provide quick and easy to understand tracing feedback. Comes supplied with three AA batteries. Ideal Industries was started in 1916 by J. Walter Becker. His belief that every product should be worth more than the price paid for it has been the core IDEAL business principle for over 90 years. Today, the many loyal distributors and customers that make IDEAL successful are a testament to Becker s original philosophy.