Yamaha Signature & Replica Series, Allen Vizzutti Inner Diam. (mm) Rim Contour/ Thickness Cup Depth Throat (mm) Backbore Playing Characteristics 16.67 semi-flat/ semi-thick very shallow 3.56 very narrow Shallow cup with smooth inner rim edge gives a clear focused sound and plays evenly in all registers. Increases the high range of many players without sacrificing tone in the low range. Gold-plated rim, cup, and inner bore.