What is meant by the installed height in a Type F variable spring?

Theinstalled height for an F-type spring refers to the distance between the baseplate and the load flange of an F-type variable spring. The minimum installedheights are specified for each size of variable spring and modifications can bemade in those cases where installed heights exceed the standard catalog values.

F-Type Variable Springs with Fully Adjustable Travel Stops
F-Type Variable Springs