These award-winning, precisely tuned percussion tubes are excellent educational devices. Plus, they are just fun to use! Simply bang the tube on a knee or on the floor and you will hear a note from the C major diatomic scale-the longer the tube, the lower the note. Each tube is color-coded and labeled with the proper musical note. Play music, and study sound and resonance at the same time. Use with tuning forks to demonstrate how wonderfully tuned these tubes are. An E-note tuning fork, for example, will not resonate in a D-note Boom Whacker. Composed of soft plastic that is rugged and safe. These tubes will stand up to years of student use and abuse. Set includes 8 tubes.