Extech CB10-KIT 3-in-1 Breaker Test Kit has everything you need to fully locate and analyze problems in a circuit breaker. The CB10-KIT includes a CB-10 Circuit breaker finder that analyzes the breaker to find the problem, a CT20 continuity tester finds which breaker has a problem, as well as an AC voltage detector to ensure power. The CB10-KIT provides all these tools in a convenient carrying case for ease of access.