Here is a standard and staple of the Jazz saxophonist’s mouthpiece collection, a Selmer Soloist D Alto Saxophone Mouthpiece, from the mid to late 1950s, with a Brevete ligature and Selmer cap. This is the more coveted, short shank model, and it is in Excellent condition.
The Selmer Soloist D has a horseshoe shaped chamber, a .075 tip opening and is perhaps most closely compared to a Meyer Number 6.
Please be sure to check the photos carefully, as I have tried to capture this mouthpiece from all angles.