Boomwhacker: These durable lightweight plastic tubes are perfectly tuned to different musical notes. Whack almost anything to produce tones. Different surfaces produce different tones but always in the same musical pitch. Diatonic Set C-C (Upper Octave) Lengths vary 12" to 50"LC1 (red) D1 (orange) E1 (yellow) F1 (light green) G1 (aqua) A1 (violet) B1 (fuchsia) C2 (red)