Night Fision night sights offer a revolutionary new design that with brighter, more vivid, aiming dots. Like all night sights, Night Fision uses self-illuminating Tritium to get the "always on" glow that makes them so effective. Night Fision sights have 30% more Tritium than most sights on the market. The Tritium insert isnt surrounded by a painted-on ring, but rather one made of a daylight fluorescing material that produces optimum visibility in daylight.