As an option you can add the or Trijicon Tritium aperture when you order the GG&G A2 BUIS for an additional price below.
OPTIONAL UPGRADE
With a TRIJICON tritium front sight and this rear, you can have 3 dot green front & green rear night sights for M16/AR15. Green lamps are warranted for 12 years from the date of manufacture. Trijicon 3 Dot night sight sets are designed and assembled with the optimum combination of strength and safety. Machined from steel rather than cast, their strength is unsurpassed. Trijicon night sights are the brightest, strongest and safest.