Metal base for connection between the selector or button and the contacts. This base is actually located inside the control panel and its purpose is to connect the selector to its contacts, whether normally open or normally closed, depending on the circuit being consulted. The base can accommodate up to 3 contacts of type 73005T or 73004T, while on the other side it only houses a selector or button. These components are attached via interlocking mechanism, the contacts have an iron lever to apply force to remove them, while the selector or button is released from the base via an 'L' hook located on the latter. By pulling it, the selector or button is disengaged from the metal base.