The Glock Store give us an overview of the Trijicon RMR HD and RCR optics which they say the company is bringing the fight to Holosun... "Trijicon is a pioneer in Micro Red Dot technology, consistently innovating in the field. Enclosed optics are highly favored by concealed carry users and those frequently exposed to harsh environments like rain. The introduction of the circle dot reticle is a welcome change for those seeking faster target acquisition with a larger reticle."