The LightKeeper Pro tool detected outages in my pre-lit Christmas tree, and I was able to repair two strings of lights using working bulbs from other strings. The bulb tester function and the ...

All it takes is one bad bulb to keep all of the other Christmas lights from lighting ... There's a bulb tester built in. Toss the old bulb, replace it with a new bulb, and the strand is repaired.

Replace any blown Christmas light fuses. Test the Christmas light bulbs with an inexpensive tester. A Christmas tree light tester is an essential Christmas light repair tool. Some Christmas light ...