Our L.E.D. Battery Gauge is an array of L.E.D.'s indicating the operating voltage of the bike's electrical system. Green L.E.D.'s represent the normal operating range of your charging system, 12.5v to 14.5v. Amber L.E.D.'s warn the rider that the bike is not charging. Red L.E.D.'s will flash if the reading drops below 10v or exceeds 15v to alert the rider of an impending stall or the possibility of damage to the battery &/or sensitive electronic components on the motorcycle. Simple two-wire connection & a compact size (about 2" x 3/4" x 3/16") make installation a breeze. A daylight sensor automatically adjusts the brightness of the L.E.D.'s. Universal fitment designed for all 12v charging systems.