E-flat clarinet
Rosario Mazzeo (April 5, 1911 – July 19, 1997) was an American clarinetist and clarinet system designer. He was born in Pawtucket, Rhode Island, grew up in Worcester, Massachusetts, and afterward lived in Boston, Massachusetts. He played first E-flat clarinet and later bass clarinet in the Boston Symphony Orchestra from 1933 to 1966.