This set includes the 400 Amp AC/DC Digital Clamp Meter, Auto-Ranging (Cat. No. CL390) and the Digital Circuit Breaker Finder with GFCI Outlet Tester (Cat. No. ET310). Klein Tools CL390 is an automatically ranging true root mean squared (TRMS) digital clamp meter. It measures AC/DC current and NCVT via the clamp, AC/DC voltage, DC microamps, resistance, continuity, frequency, capacitance, and diodes via test leads, and temperature via a thermocouple probe. It features a high visibility, reverse contrast LCD display that optimizes view ability both in dark or bright ambient lighting. The Klein Tools ET310 Circuit Breaker Finder with Integrated GFCI Outlet Tester is a digital circuit breaker finder used to locate the correct circuit breaker in a panel to which an electrical outlet or fixture is connected. The Transmitter is connected to the electrical outlet or fixture in the circuit while the receiver is used to scan the breakers in the circuit panel. The Transmitter also features a GFCI outlet tester.