Greenlee 801K Premium Tone and Probe Kit LED for visual signal strength indication, continuous on feature Microprocessor controlled circuitry, Five minute auto shut off, low battery indicator The 200FP probe features AC hum filtering, LED for visual signal strength indication, continuous on feature, 5-minute auto shut off and low battery indicator 77HP tone generator can be used on twisted pair, single conductors, coaxial cables, de-energized AC wiring. Battery operated, 9V not included