Ring with a wave pattern..
Note: Depending on the material you choose, the ring will stretch a litle over the finger so make sure to always choose a smaller inner diameter then you normally would with conventional rings to create a snug fit around the finger.
Other sizes:
(16mm / 0,62inch) (17mm / 0,66inch) (18mm / 0,70inch) (19mm / 0,74inch) (20mm / 0,78inch) (21mm / 0,82inch) (22mm / 0,86inch) (23mm / 0,90inch) (24mm / 0,94inch) (25mm / 0,98inch)