This is a “early Babbitt” series metal Otto Link Super Tone Master mouthpiece for the tenor sax. This piece was originally a 5* (large font) but has been opened to Sebastian Knox to a 6*, measuring .096”. His work was solely on the tip and rails, with some flattening on the table, with the original factory baffle left intact. That's important on these early Babbitt pieces, as they typically feature a more defined, higher baffle than the early Florida Links. This is a good playing piece, with more bite and edge than you'll often find on a Florida piece, while taking your air very efficiently.