Patent ID: 8641210

Claim:
A device comprising a retro-reflective marker sphere comprising: a core ball comprising: a generally spherical body portion, a mounting base extending exterior to and away from one end of the body portion of the core ball, and a mounting recess having a recess opening in the mounting base and extending into the body portion of the core ball, and a retro-reflective covering on the core ball, the retro-reflective covering comprising an opening through which the mounting base of the core ball extends, wherein the mounting recess includes one or more interior engagement structures for engaging one or more exterior engagement structures of a mounting post when the retro-reflective marker sphere is mounted on the mounting post, wherein a flat lower surface of the mounting base is spaced proximally from a lower edge of the opening of the retro-reflective covering, and wherein the mounting base has an alignment indicator on one or more sides of the mounting base.