Weltmeister Rubin 30/60/II/3 - the Rubin is the only instrument of its kind being built. The physical size and weight is equal to the Perle 26/48. It offers an additional 4 keys going down to the low 'G' which allows for full chords to be played with the right hand. The bass side offers 60 basses covering all keys. Thus this instrument is a favourite of performers that need the full range of tonality but want to cut down on the weight.