The knob.

Using the knob(s) allows positioning more discrete values on the same area compared with the buttons. The set value is always shown in the knob-center, so it is not necessary to find what button is pressed. Moreover, working knob looks more aesthetically pleasing than buttons.

These control knobs were specially designed to be used in USB oscilloscope, that's why there is a number of particularities to know when usefully operating these controls that can save you time and increase your work comfort and productivity.

1. Using the mouse - when left clicking on the knob(s) (cursor takes a hand form) and moving the mouse but not exactly over the knob. When moving the mouse the knob cursor will be positioned along a radial line drawn from the center of the knob to the mouse cursor position, i.e. like mechanical control knob, and very intuitive - you ove the edge of the knobs dial to the desred value. Upon clicking on the knob this element is within the input focus, i.e. can be key- or mouse wheel operated even if the mouse cursor is not on the knob. It is useful if you know that most of other usable elements are out of input focus, i.e. you can change the different triggering modes/levels and adjust the sampling period or peak-to-peak voltage by the mouse wheel.
2. Using the mouse wheel.
3. Using the keys Left, Right, Up, Down, Home, End, PageUp, and PageDown.

Also, note that when the mouse cursor is over the knob, a prompt regarding the value to be set/set is shown on the status bar.