Boomwhackers 7-Note Treble Extension SetExtend your Boomwhacker range upward! Starting just above the highest note in the 8 Note C Major Diatonic Set (Item #BWDG, sold separately), this 7 Note Treble Extension Set includes High C#, D, D#, E, F, F#, and G. Tubes range in length from 7" to 11". Found in most elementary music classrooms and music therapy programs around the world, these affordable, color coded, tuned percussion tubes provide an opportunity for any age and ability to experience