Meprolight Tritium Combat Night Sight Set for AR-15 with 4-dot rear aperture.
The Meprolight ML31619 set has a 4-dot peep rear with a new design front sight that has a round dot. This sight set still has the 5-slot base and can be used on either the A1 or A2 style AR15 rifles.
The tritium green dot sight system of Tru-Dot sights offers the best low light performance of any night sights. The Meprolight sights system provides self-lit dots as an aiming reference, identical in appearance and location under all light conditions.