Tritium night sights transition from standard white dot sights during the daylight, to glowing green dots in the the dark. Tritium does not need batteries and does not need to be charged with light.  Product Specs: - Traditional tritium night sights - Uses the brightest tritium available - CNC-machined steel construction - Green front and rear - Fits standard holsters - Snag-resistant design Fits the following model Taurus Firearms: G3c G3 GX4 FOR G3 MODELS WITH STEEL FACTORY SIGHTS. WILL NOT WORK ON POLYMER SIGHT MODEL.