Prologue by Seles Alto Saxophone Mouthpiece. The Prologue mouthpiece is easy to play and its response is fast and predictable. These qualities and its attractive price, make it a great choice for beginner saxophonists. Drawing on Selmers extensive anknowledge and experience, a new material has been chosen that offers outstanding acoustic qualities, similar to the hard rubber used in the conception of the Henri SELMER Paris mouthpieces, as well as a perfect repeatability in production. Prologue mouthpiece is fitted with its ligature and cap.