The Mini SpiderCapo is for narrow necked instruments. These include, but are not limited to: Banjo, Ukelele, Mandolin and Bouzuki.
Users report that because the SpiderCapo clamps over the fingerboard, and not behind, it can also be used on the Mountian Dulcimer.
The purpose of the Mini “Spider” is to Capo each string individually making possible hundreds of tunings without de-tuning your instrument.
As banjo players in particular like to tune in different ways to start with, SpiderCapo will multiply each tuning by the same factor making hundreds and hundreds of tunings available!