If this ring had existed in the 16th century, Michelangelo would have worn it without a doubt. Material: Stainless steel or 925 Sterling silverWeight: 12.6 grams PACKAGING Every order comes with a Kuurth's sphere and an owner's guide. SIZE GUIDE - The ring should fit you comfortably; it should be tight enough not to fall off but loose enough to slide over your knuckle. - Measure the circumference of the finger where you are going to put the ring with a sewing meter, if you do not have a sewing meter you can cut a strip of paper, surround the finger with the strip and make a mark. - Then measure that section of the paper with a ruler or tape measure, the measurement you get is the length. - Measure the finger a couple of times to avoid mistakes. OUR SIZE DIAMETER LENGTH XS 16 MM - 0.629 INCH 50 MM - 1.968 INCH S 17.3 MM - 0.681 INCH 54.34 MM - 2.139 INCH M 18.5 MM - 0.728 INCH 58 MM - 2.283 INCH L 19.7 MM - 0.775 INCH 61.8 MM - 2.433 INCH XL 21 MM - 0.826 INCH  66 MM - 2.598 INCH