A horizontal histogram of total volume traded at each price level over a chosen session or period, derived from Market Profile theory. Key levels read off the profile are the POC (highest-volume price — the session's fairest), VAH and VAL (upper and lower bounds of the 70% value area), high-volume nodes (acceptance zones) and low-volume nodes (rejection zones the market moved through quickly). The profile reveals where price was accepted versus rejected, which traditional time-based charts cannot show.