This Boomwhackers BWDG diatonic set includes 8 tubes tuned to the notes of the C major scale. By gently striking nearly any surface (tables, chairs, floors, your thigh or hand, your shoe…whatever!) you can produce a full, audible tone. Different surface produce different sounds, but the pitch always remains the same.To extend the range of this Boomwhacker set, we recommend adding the Octavators for Boomwhackers. By placing one of these caps on the end of any Boomwhackers tube, the pitch is automatically lowered by eight tones or one full octave. Specifications:Tubes range in length from 12" - 24"Each Boomwhacker is tuned to a different pitch and has a unique color: C1 (red) D1 (orange) E1 (yellow) F1 (light green) G1 (aqua) A1 (violet) B1 (fuchsia) C2 (red)