We say :

Boomwhackers are sets of tuned percussion tube that are a brilliant way to get children engaged in music in the classroom setting. Colourful, dynamic, physical and, of course, musical they help you teach about melody and rhythm in a fun and engaging way. We can supply a range of the Boomwhacker products to our customers. Do get in touch if you need further information about this dynamic set of musical instruments.

Boomwhacker say :

This set consists of the 5 sharps/flats for the bass octave. It combines with the Bass Diatonic Set to yield a lower chromatic scale, or combines nicely with the Chromatics set for an extended range of notes. Tubes range in length from approx 27" to 47".