DEG Comparison Chart:

10 - Deep cup depth, 16.80 Approx. cup diameter, Medium Wide rim shape.
Compare to Bach 10 French Horn Mouthpiece

11 - Medium cup depth, 16.55 Approx. cup diameter, Medium Wide rim shape.
Compare to Bach 11 French Horn Mouthpiece

12 - Medium cup depth, 16.50 Approx. cup diameter, Narrow rim shape.
Compare to Bach 12 French Horn Mouthpiece