ORB Range Marker is a trading indicator designed to automate the plotting of Opening Ranges for the Opening Range Breakout (ORB) strategy. It identifies and visually maps the initial high and low price boundaries during the first minutes of major trading sessions—Tokyo, London, and New York—highlighting key early market activity. Users can customize the duration of the opening range, choosing intervals such as 5, 15, or 30 minutes. The indicator extends horizontal support and resistance lines from these ranges across the chart, aiding traders in spotting breakout and retest levels as live price action unfolds. It is optimized for performance with lightweight code to prevent chart lag and offers customizable color palettes suitable for both light and dark chart backgrounds. The ORB Range Marker supports multiple asset classes including Forex majors, indices like US30 and GER40, commodities such as Gold and Oil, and cryptocurrencies. This tool is intended to assist day traders and scalpers in executing high-probability breakout and mean-reversion trades by clearly delineating critical early session price zones.