Put one of these Octavator caps on the end of a Boomwhacker tuned plastic percussion tube, and you've lowered the tone by an octave (8 notes lower in sound)! Play the tubes as usual or hold them vertically and tap the capped end on the floor. An economical way to extend your range of notes, as well as an easy way to make lower notes more accessible. For example, a capped tube from the short diatonic set (item 200346, available separately) can be much easier to handle than a longer bass tube. Package of 8 is enough to cover any one set of Boomwhackers (each set of Boomwhackers is available separately).