Namfleg ring sizes are equivalent to the inside diameter of the ring in millimeters. Choose a ring you already own and measure the inside diameter of your ring with a ruler. Now that you know the inside diameter of your ring in millimeters, you can easily choose a right Namfleg size for you. Keep in mind that rings with a wide band sit more tightly on a finger than thin ones. Therefore, their circumference should be slightly larger than that of their skinny counterparts.