The Sperry ToneProbe Kit takes tone and probe to the next level. Engineered for comfort over long periods, the ergonomic over molded rubber construction of both transmitter and receiver will withstand all the punishment of everyday use. The transmitter features easy onehanded control of tone and continuity functions. Three distinct tones allow easy audible identification for multiple traces. For greater operator convenience, the receiver’s 360 degree indicator light allows visibility from any angle. And when necessary, you can override the speaker with an earphone jack for silent operation.