The HS503R is a micro red dot optic that features Holosun’s new rheostat dial to adjust brightness settings. Employing Holosun’s ultra-efficient LED technology, The HS503R can achieve a battery life of up to 5 years. This optic also features Holosun's Multi-Reticle System™ with three choices: A 65 MOA circle and dot reticle, or a 2 MOA dot only reticle.