TFX Tritium and Fiber-Optic Xtreme Handgun Sights for Ruger Pistols UNMATCHED VISIBILITY in all shooting conditions, night or day; GLOWS IN THE DARKno batteries or light exposure required Front sight FOCUS-LOCK RING for even faster focus FX SEALED CAPSULE DESIGN provides maximum protection and durability; FORTRESS FINISH provides a permanent protective coating; Impervious to oils, chemicals, cleaning solvents, and ultra-sonic cleaning processes CONCEALED FIBER cannot be seen by target; SNAG RESISTANT DESIGN fits standard holsters MACHINED AND ASSEMBLED IN THE USA with quality Swiss Tritium for maximum brightness; 12-YEAR LIMITED WARRANTY; Patented