■ Diameter: 7.1 inches (18 cm) ■ Leather: buffalo leather ■ Size swatch (model height 170 cm) diameter 15 cm height 4 cm diameter 18 cm height 4 cm diameter 21 cm height 4 cm ※ Click the image to get larger. Diameter = The face of the drums striking surface. Height = The height when the surface is placed upward. Size Guide: 8.3 inches (21 cm): Elementary school age to adults; 7.1 inches (18 cm): Elementary school years and kindergarten; 5.5 - 6.3 inches (14 - 16 cm): Kindergarten and nursery. *Recommended for sizes only. It seems to be better to choose a larger size if you are not sure which one is between your previous orders.