These indexing plungers combine the indexing function (spring loaded retractable pin designed to mate with a series of indexed position holes) with a clamping function (threaded stud that can be tightened for clamping in an infinite range of positions).
An application example is an awning that is generally positioned in set series of indexed positions by extending the pin into one of series of holes drilled in the support rod. However, there are times when a very specific angle may be desired—to shed the rain in a given direction, or block the sun without obstructing the view—in which case the threaded stud can be tightened anywhere between an indexed position.