UMI Christian Lindberg Series Trombone Mouthpiece 10Cl Silver CHRISTIAN LINDBERG TROMBONE MOUTHPIECEMouthpiece 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