'Tis the season to untangle last year’s Christmas lights... only to find a few bad bulbs in the mix. Don’t trash that string yet: Now you can find the problem and fix it with the LightKeeper Pro.

Let's face it, Christmas trees can be a bit of a headache. From tangled lights to that inevitable burnt-out bulb that plunges the whole strand into darkness, the festive cheer can quickly dim. Light ...