The Matris is slightly smaller than the EVO measuring just 286mm wide It is 2 voice 3 row treble with no voice changes,it is MM tuned,it is 18 bass 3 voice with the optional thirds stop fitted. It is the same spec as the Castagnari Big 18 but the larger size gives a more resonant sound and larger buttons. Comes with Hard case,2 straps 4 buckle covers