The trumpet mouthpiece is made of metal material with smooth and wear-resistant surface. Easy to wipe and keep them clean, and the sound quality is great. | 5C and 3C sizes are from small to large, including outer ring, inner cup, inner diameter and inner tube, which all are from small to large. | There are 2 sizes for trumpet players to choose. 5C is suitable after some exercises, then 3C is suitable for the professional players. | Size: 1.1in x 3.3in x 0.39in. | It would be a good gift chioce for freinds or children.