The HS503R is a 20mm micro sight designed for rifle and carbine applications. HS503R features a Rotary switch to select reticle intensity, Holosuns Red Super LED with 50k hour battery life, and MRS (Multi-Reticle System) with 10 daylight and 2 night vision compatible reticle intensity settings.The HS503R 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 height rifle applications. Additional features include rubber lens covers, and a battery compartment integrated into the Rotary switch for the 2032 battery. HS503R is a versatile sight for users of all levels.