Features 100% Brand New. Color: As picture Size:16.5mm:Diameter about 16.5mm, circumference about 51.9mm 17.3mm:Diameter about 17.3mm, circumference about 54.4mm 18.1mm:Diameter about 18.1mm, circumference about 57mm 18.9mm:Approximately 18.9mm in diameter and 59.5mm in circumference 19.8mm:Approximately 19.8mm in diameter and 62.1mm in circumference Material: alloy Package Content: 1 PC Kindly Tip: 1. Conversion: 1 inch= 2.54cm Size Approximately : These size is about Asian Size,general get one size smaller than US/EU size,Please reference to the size chart in the picture. Item Measure by hand, it could be 1-3cm different. hope you can understanding, will be sincerely appreciated. 2 .Please be reminded that due lighting effects, monitor's brightness/ contrast settings etc, there could be some slight differences in the color tone of the website's photo and the actual item.