During the 1950s and 1960s the Brilhart Tonalin was the choice of most lead alto players in New York. An incredible number of great recordings were made with this mouthpiece. I live in Florida and I've worked with some of these great players after their retirement, and they are still playing Tonalins.
Full disclosure:
I don't personally play a Brilhart Tonalin. I play an early Selmer Mark VI, usually with an old Meyer mouthpiece. My backup alto is a wonderful Selmer Cigar Cutter, and when I tried a Tonalin on that horn, I realized why the old pros used that setup.
Shameless even further disclosure:
I currently have one of the very best Tonalins for auction on ebay right now. It's a number 4, which is a larger facing for a Brilhart, and it's a Great Neck model, one of the best:
Nice solid mouthpieces on alto. Same for the ebolin which is the same piece but is black instead of white. Benny Carter played an ebolin (and once in a while a tonalin) for years on his mark VI.