Silver Crystal Ring size 10.25, 20mm inner diameter | eBay
Ring size | How to measure | Argos
Ring Size Guide Millimeters —
KW-trio 12pcs DIY Disc Binding Ring T-type Mushroom Hole Loose Notebook Notepad Binder Fixing Disc Buckle 10mm/15mm/20mm/25mm for Travel Office Home School Students - Walmart.com