The Light Keeper Pro includes a piezoelectric shunt energizer as well as other diagnostic and convenience tools.
Miniature holiday light set failures occur when an individual bulb “shunt” fails to energize when a filament burns out causing a section of lights to go out instead of just one light bulb. An electrical pulse through the defective bulb activates the shunt restoring the remaining bulbs. site 
Ulta-Lit Tree Company originated as the pioneer in affordable pre-lit Christmas trees in 1996. Frequent light set failures led us to search for an affordable solution. In 2004, the LightKeeper Pro was invented.
In 2011, Ulta-Lit Tree Company was ranked number 4170 on the list of Inc. Magazine’s 5000 Fastest Growing, Privately Held Companies. In 2012, the company advanced on the list to the ranking of number 3838. In 2013, the company achieved a ranking of 3191.
.
Our high-end artificial tree exists to display a lifetime accumulation of hand-made ornaments. Here in the Northwest where tree farms dot the landscape we once considered it an obligation to decorate a natural trees with newly purchased lights and then discarded both in January. No more.
We've owned and reassembled the same pre-lighted tree every year for a decade. In this time we have learned to check for and replace numerous burned out bulbs working section by section in good daylight while setting up the tree. This maintenance could keep the same light sets working for years to come.
But with old lights failing now a routine we can easily have our holidays interrupted with dark strings. Shunt shock will bring a set back to life like magic.