Simple Solution Spot Spotter HD is an Ultraviolet LED Urine Detector that reveals hidden urine spots and illuminates urine that is undetectable to the human eye. Spot Spotter HD helps identify the source of an odor so that it can be properly treated and removed. Works on any surface including carpet, upholstery, concrete, tile, sheet rock, and more. Contains 21 powerful LEDs. Requires 3 AAA batteries (included).