The sparkline on each row shows the bank's rate over the selected range. Green = moving in your favour (cheaper), red = moving against you, grey = flat. The heatmap above shows daily ranks across banks; the “+X.XX vs best” on the right tells you what picking the wrong bank costs you today. Click a bank name for that bank's full market-context chart. For buying foreign you want the lowest LKR (cheapest). Actual rate at the branch / app may differ; this is a comparison aid, not a quote. CBSL is the central-bank indicative-rate benchmark, useful for spotting outliers but not a rate you can transact at.