Greg Black 4G Symphony Tenor Trombone Mouthpiece, Large Shank

Cup Diameter: 26.1mm, 1.032” Rim Width: Medium Wide Bore: 'K', .281"

Model: 4GS Cup Depth: Medium

Model: 4GSD Cup Depth: Slightly Deeper 4GS

Model: 4G-5G Cup Depth: Medium Deep

Model: 4G Cup Depth: Deep