The CV1 and CV2 tabs open up a tab with a set of frequently used unit conversions. (The entire set of unit conversions is available from the “Conversions” menu.) To get a detailed description of the conversion in a given button, move the mouse pointer over the button.
All conversion functions operate on the value in the calculator active calculation level, as do all other function buttons above the tab area except the Matrix buttons. Each conversion button can convert either direction depending upon whether you right or left click it. For example, left-clicking the [ F⬄C] button will convert from Fahrenheit to Celsius, while right-clicking will convert from C to F.