VivaRhythm Boom Series Djembe Set deliver a lower overall tone with outstanding projection. The synthetic shell features a rubber bottom to prevent slippage or scratching and is shaped to allow air to escape from the shell. This creates low fundamental tone that resonates fully. The BOOM SERIES pre-tuned synthetic heads give a robust attack. Each drum is stackable inside the other for easy storage and transportation.Size: 9 1/2" head diameter, 43,8 cm height and 12" head diameter, 61 cm height. Materials: Synthetic shell, Synthetic head. Features: Synthetic shell is perfect for outdoor playing.