4x32 crosshair models are designed to provide enhanced target identification and hit probability for the M16 and AR15 rifle out to 600 meters to 1200 meters, except for the TA01LAW model which does not feature a BDC reticle. They have a tritium illuminated reticle for night and low light use. This means the center are a of the crosshair pattern is illuminated in low light or complete darkness. The original TA01 models will have black crosshairs during the daytime and TA11 and TA31 crosshair models will illuminate during the day as well using fiber optics. The fiber optic light collector adiusts reticle brightness according to light levels. This auto-matically balances aiming point brightness.