This is a vintage Giardinelli trumpet mouthpiece given to Al Cass from Louis Armstrong when my father made Mr. Armstrong a custom mouthpiece! One of the most prized mouthpieces in my late father's legendary mouthpiece collection. Exhibits considerable use, tested but never used by my father.
My father mentions this piece in his notebooks, it is 1 of only 2 Giardinelli's in his collection, the other a Maynard Ferguson, inscribed MF, which sold in Guernzey's 1st Jazz Auction in NYC 2005. (( notes on mouthpiece shown, left/center and painted over in purple to hide specs.))
For comparison, thought I'd post these 3 together. Left is the Dizzy Gillespie Al Cass 2-24A(which was re-plated by Gillespie at some point), middle Harry James Parduba 5 double cup and right Louis Armstrong Giardinelli(no size indicated)
Armstrong/James/Gillespie. What I see, or realize, in this pic is that ALL 3 pieces have a "double" cup of sorts. The Giardinelli and Cass' first cup is the "bite", then goes into the "second cup" more discreetly. Where the Parduba seems to have no bite and is much more distinct between 1st and 2nd cup.