Use the links below to select your size.The ring on this page is a US Size 10.5
US size 12.5 interior diameter: 21.7mm
US size 11.5 interior diameter: 21.0mm
US size 10.5 (this page) 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