Fight fleas while you sleep with the pesticide-free Harris Plug-In Nite Light Flea & Insect Trap. Complete with a sensor that automatically detects when it’s dark, this plug-in light emits a slight warmth that attracts fleas. Once the fleas reach the light, they get stuck on a glue board. Once the glue board is filled, you can replace it with a new one for ongoing use. This trap is great when combined with other flea treatments and is an almost completely effortless way to fight infestation.