CHRISTIAN LINDBERG TROMBONE MOUTHPIECE Mouthpiece rims are sized in close relation to each other so that changing from one to another is extremely comfortable. For example the 13CL alto mouthpiece is specifically designed to ease the transition to and from the 2CL or 4CL large bore tenor mouthpiece. Similarly the 15CL alto mouthpiece makes it easy to switch back and forth from the 5CL large bore tenor mouthpiece. The Lindberg cup rim is slightly thinner than on other brands which makes flexibility and movement from top to bottom register easier. Also the inside of the rim is slightly sharper which facilitates articulation. Expand your musical horizons with the new Christian Lindberg trombone mouthpiece from UMI. Model Shank Cup Diameter Description 2CL Large 25.55mm Big dark open sound 4CL Large 25.60mm Slightly brighter than the 2CL with substance and richness 5CL Large 25.83mm Bright clear and distinct sound; easy top register and improves endurance 10CL Small 25.15mm Full and clear sound 13CL Small 25.90mm Clear distinct sound on tenor trombone and full open sound on alto trombone 15CL Small 25.75mm Distinct and clear sound with body and richness on alto trombone