It's the world's brightest handgun sight in any light, with tritium specially formulated to give you industry-first brilliance from broad daylight to midnight. These self-illuminated, fixed tritium sights feature an extremely bright colored ring front sight in your choice of green, yellow, or orange, delivering supreme visibility as a night sight or day-night sight. Contrasting front and rear sight colors help shooters focus on the front sight quicker for faster target acquisition in all lighting conditions. Because you can't predict when everything will depend on your sight's visibility, you can count on Hyper-Bright. Every time.HYPER-BRIGHT CONCEPT: The MEPRO Hyper-Bright fixed Day and Night Sights offer the most reliable illumination for day or night. Mepro Hyper-Bright fixed sights feature an extremely bright fluorescent contrast colored ring in green or orange for fast target acquisition in the daytime. The yellow ring option is the sole option with phosphorescent paint that charges with light and glows in lowlight conditions for a short time in conjunction with the tritium. As a result, both rear and front tritium sources appear green in lowlight and nighttime.ALWAYS ON: Premium grade green Swiss-made Tritium vials in the front and rear sights allow for low light and nighttime conditions. The U-notch shape on the rear naturally directs your eyes to the top of the Front sight. No batteries, no switches - always on, always ready 24/7 for 12 years. Maintenance-free can be mounted directly with no modifications. Direct factory replacement, recommend replacing as a set.