Technically it's a Roland Rhythm 330, but I call it Boomchicka because that's the sound it makes. It's a cheesy organ beat box minus the cheesy organ -- for soloists or bands without drummers, I guess. Each button is a different dance rhythm: Waltz, Slow Rock, Rock Beat, Bossa Nova, Mambo, Cha Cha, Beguine, Rhumba, March, and Swing. It's fun to push in two (or even three) buttons at once to make crazy new mutant rhythms -- anything plus waltz is particularly wonky. Purchased at a garage sale for 10 bucks.