Push/Pull
Reference
Mode:
Object and Edit Modes
Tool:
Toolbar ‣ Shrink/Flatten ‣ Push/Pull
Menu:
Object/Mesh ‣ Transform ‣ Push/Pull
Push/Pull will move the selected elements (objects, vertices, edges or faces) closer together (Push) or further apart (Pull). Specifically, each element is moved towards or away from the center by the same distance. This distance is controlled by moving the mouse up (Push) or down (Pull), numeric input or through slider control.
Usage
See below for the result of using Push/Pull on a number of different elements.