Our hammered and aged silver 'spike' ring available in 3 sizes; small, medium and large. This small version has an inner diameter of around 16.5 mm (US size 6.5). 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.