This beautiful towel/clothes hook is available in three different sizes:
Small: Depth 30 mm (1.18 in.) (diameter 18 mm (0.71 in.))
Medium: Depth 35 mm (1.38 in.) (diameter 23 mm (0.91 in.))
Large: Depth 40 mm (1.57 in.) (diameter 26 mm (1.02 in.))
The screw is fastened behind the hook.