According to the ad copy for the Jazz-Yo Regulus II:
The Regulus II is an undersized design with a really different rim shape. The undercut profile and overhanging rim equip this smaller throw with some really big performance… And with the unique design, the Regulus II has all maneuverability you expect from undersized throws…
The specs list it as having a 55.6mm diameter, a 44.8mm width, a (ridiculously wide) 5mm gap, and a weight of over 66g. Nothing about this yoyo is undersized as far as I can tell. What am I missing here?