Vincent Bach Corp No. 8 Mouthpiece with Standard Trumpet Shape 1965-1969.  The Vincent Bach catalog lists this mouthpiece for Trumpet, Cornet & Fluegelhorn. It is described as having a deep cut with an approximate cup diameter of 16-20mm, a rim shape that is fairly wide with rounded inner edge and will produce a rich, full, clear tone.  The makers mark "Vincent Bach Corp" with no "." after the corp logo dates this to 1965 to 1969.