The Radial Gauge is one of the flavours that are available in the RadGauge control family. It represents the value on a circular scale much like car speed dial.
The specific properties that make it different are related to the pointer and rotation angles - the pointer is an arrow and its size is a percentage of the gauge size while the entire scale can be rotated as specified by the StartAngle and EndAngle properties.
This demo shows the basics of the Radial Gauge control. Examining the code will show the basic markup - tags and properties, the code-behind logic will show the code structure.
Setting a value that is outside of the range will result in either a min or max value being set, if you disregard the instructions in the value textbox before clicking the configure button. The pointer's Cap size is a percentage value from the entire gauge control where 1 is the entire gauge and 0 means no pointer.