Harry Potter Stainless Steel Lightning Bolt and Glasses Ring. This Harry Potter lightning bolt and glasses ring is made of stainless steel, designed in the familiar shape of Harry Potter’s scar and his distinctive glasses. Available in three sizes: Small (L), Medium (M), and Large (P). The Carat Shop are the official licensed manufacturers of Harry Potter jewelry on behalf of Warner Bros. Ring Size Chart –              Inches   MM      USA    UK    HK Large      0.714     18.14    8         P      18 Medium 0.666      16.92    6.50   M     14.5 Small      0.618      15.7      5        J       11