US: 10mm Standard Hoop to United Kingdom Size 20G Standard Stud

US: 10mm Standard Hoop: Features a post thickness of 1 $\text{mm}$ (0.0394 $\text{in}$), hoop inner diameter of 10 $\text{mm}$, gemstone carat equivalence of N/A (Hoop), and earring style Hoop / Classic Fit.

United Kingdom Size 20G Standard Stud: Features a post thickness of 0.8 $\text{mm}$ (0.0315 $\text{in}$), hoop inner diameter of 0 $\text{mm}$, gemstone carat equivalence of 0.25 ct - 0.50 ct, and earring style Stud / Minimalist.