TFX Tritium and Fiber-Optic Xtreme Handgun Sights for FN 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 TFX 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 Fits FNH FNP-45 and FNX-45