Mini Harmonicas- Additional types of harmonicas are available for special purposes like harmonica trios, groups, or orchestrals. Most of these are made by the Hohner Company, but other companies may carry some as well. This group includes: double-reed harmonicas (octave and tremolo tuned), bass harmonicas, chord harmonicas, Polyphonias, and miniture 4-hole harmonicas. These harmonicas are not recommended for beginners interested in blues and country playing nor useful for most beginning instructional materials. Mini harmonicas are just fun!