A single leather body is connected to a die cast aluminium shell, onto which is grafted the shaft-base. The main technical problem was how to combine different technological worlds. Through the technology of aluminium die-casting every complexity in the designing of detail was resolved through a single moulding process. The sandwich comprising two leather sheets and a central one in polypropylene and the fastening system borrowed from the electrical sector solve the connection of the parts. The invention of form springs from experimentation and matching of materials.