1. Conductive rubber keypad with an integral semi-conductive pill or puck on the back side.
2. Non-conductive rubber keypad that presses against a metal snap dome switch.

The term rubber keypads can refer to just the molded silicone rubber part or the entire keypad assembly including the supporting printed circuit board, and sometimes a decorative bezel. The molded rubber part is a component of a larger keypad assembly and needs to be understood as part of an assembly rather than a stand-alone component.