When the lights go out, your sidearm doesn t need to be left in the dark. 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 it simply glows! For Glock 17 / 17L, 19, 22, 23, 24, 26, 27, 33, 34, 35, 38, and 39 (Excluding M.O.S. models) Traditional tritium night sights Uses the brightest tritium available CNC-machined steel construction Green front and rear Fits standard holsters Snag-resistant design