The Trijicon RMR Type 2 RM01 uses Auto-LED brightness control - an ambient light sensor sets illumination level automatically. The 3.25 MOA dot is the same precision-friendly reticle as the manual-LED RM06; the difference is whether you want to manage brightness yourself or let the optic do it. Specs: Reticle: 3.25 MOA Auto-LED red dot Illumination: 8 ambient-light-driven brightness steps (no manual control) Housing: 7075-T6 forged aluminum, hardcoat anodized matte black Adjustment: 1 MOA windage and elevation, 150 MOA total each direction Battery: CR2032, side-loading Weight: 1.2 oz Footprint: Trijicon RMR Waterproof: IPX7, submersible to 65 feet Auto-LED vs Manual: Auto-LED is the right call for duty/carry where you don't want to think about brightness when drawing into different lighting (going from bright daylight to a dim interior, for example). Manual (RM06) is the right call for competition where you want exact control.