Holosun HE503RGDThe HE503R GD (Gold Dot) is a 20mm micro sight designed for rifle and carbine applications. HE503R GD features a Rotary switch to select reticle intensity, Holosuns Gold Super LED with 50k hour battery life, and MRS (Multi Reticle System) with 10 daylight and 2 night vision compatible reticle intensity settings. The HE503R GD housing is made from 6061 aluminum and includes both a lower 1 3 co witness mount (1. 63) and a low mount (. 75) for low comb