Kewtech Fuse Finder Kit is a two piece kit and comes with a mains lead for socket outlets. ACC016E test leads are optional for testing lighting circuits. Self learning module increases accuracy as you sweep over the breakers. The transmitter is powered from the supply so does not need batteries. It injects a signal into the circuit that is then picked up by the receiver at the fuse board. The receiver – this cleverly auto-tunes when scanning a bank of fuses/MCBs. At least two scans are required so that the receiver can adjust its sensitivity to detect the strongest signal and hence the correct fuse for the circuit under test.