When there is a problem with holiday lights, the LightKeeper Pro Light Tester has the solution. Use it on Incandescent light sets and pre-lit trees. Features an audible continuity detector that pinpoints the problem by tracing the circuit to the point of interruption. There is an attached LED headlight to guide your way and the 3-way bulb puller gets tight bulbs out with ease. The storage compartment houses your bulbs and fuses. Quick-fix trigger fixes internal bulb failure Features a voltage detector Tests fuses and light bulbs LED headlight aids visibility for easy repair Storage compartment within handle for spare bulbs and fuses There is an instructional video at lightkeeperpro.com B4