Golf club head consisting of a balance plane, that subdivides the head, that derives markings visible on the club head face, containing multiple Sweet Spots indicating the ideal points of contact with a golf ball regardless of whether the golf ball is lying on the ground, on a golf tee or otherwise,...http://www.google.co.uk/patents/US20040092328?utm_source=gb-gplus-sharePatent US20040092328 - Golf club clubhead and golf club head component with markings determined in conjunction with the balance plane with, and without, parallax correction to be used for alignment and visual aid purposes, with tools, markings, methods for locating same together with methods of using same
