An endoprosthesis that includes a composite having a metal matrix and a plurality of stiffening particles in the matrix. In response to the signal, the handsets activate alerting means to alert users of the handsets to the need to answer the call. The gear control device has a first drum control device associated with the first shaft, a second drum, control device associated with the second shaft, and an actuation unit which is arranged to bring about rotation of the first and second drum control devices in a synchronized manner.