Our hammered and aged silver 'spike' ring available in 3 sizes; small, medium and large. This large version has an inner diameter of around 21 mm (US size 11.5). These rings are all slightly adjustable since they are 'open'. At the thickest point, the spike is 4 mm x 2.5 mm and at it's narrowest 3 mm x 2 mm. The spike 'head' measures 7 mm x 5 mm.