Use the links below to select your size.The ring on this page is a US Size 4.5
US size 10.5 interior diameter: 20.2mm
US size 9.5 interior diameter: 19.4mm
US size 8.5 interior diameter: 18.6mm
US size 7.5 interior diameter: 17.7mm
US size 6.5 interior diameter: 16.9mm
US size 5.5 interior diameter: 16.1mm
US size 4.5 (this page) interior diameter: 15.3mm