Testboy with flashlight function. Non-contact voltage testing. The WAGO Testboy 206-804 is capable of detecting live wires using the integrated circuit at the tip. When an AC voltage of 12 volts is detected, the white cap lights up red and an alarm sounds. No current flow is required! The voltage tester indicates the following: live conductors, cable breaks, blown fuses (in cartridges or holders), faults in switches, and defective bulbs in light strings.