Innovative Percussion She-e Wu Series - Hard Concerto Marimba Mallets Medium Hard Plastic cores to create a bright tone qualityHand-selected unfinished natural birch handlesTightly wrapped with durable and organic bamboo yarnElongated shaped mallet heads This concerto model is tightly wrapped with durable and organic bamboo yarn All models are built on natural birch handles Each captures the unique style, sensitivity, and essence of the artist that is She-e Wu