This is an excellent condition Selmer mouthpiece, from the "oval stamp" era.  It was originally an open HS** but I meticulously brought it down to an orchestral 1.04-37.  It plays well now, whereas prior to my work it just required too much work to play.  

The chamber in this mouthpiece is typical Selmer from the Mid-Century era - Perfect!   Those mouthpieces were amazingly well made, and this is no exception.   The facing allows for medium to medium-firm reeds work with springy enthusiasm,  making a lovely effervescent, strong, warm, and rich sound that is eager to play.
 
I love Selmer mouthpieces!  In fact, back in my earlier career I played on a fantastic Selmer mouthpiece of the same era for years.  It taught me much about what to look for in a good mouthpiece, in good rubber, and in how to bring out warmth expression, and nuance by celebrating resonance.  I learned to use softer reeds, and minimal embouchure pressure.  It was an amazing period of discovery which I shall always be thankful to Selmer for.  
 
No returns on mouthpieces, but if you decide that it isn't the mouthpiece for you I'll take it back as credit towards your purchase of a BEHN Flagship mouthpiece (EVOKE, EPIC, VINTAGE).