US: 20mm Medium Hoop to United Kingdom Size 18G Standard Stud

US: 20mm Medium Hoop: Features a post thickness of 1.2 $\text{mm}$ (0.0472 $\text{in}$), hoop inner diameter of 20 $\text{mm}$, drop length of 20 $\text{mm}$, gemstone carat equivalence of N/A, and earring style Hoop / Everyday Medium.

United Kingdom Size 18G Standard Stud: Features a post thickness of 1 $\text{mm}$ (0.0394 $\text{in}$), hoop inner diameter of 0 $\text{mm}$, drop length of 6.5 $\text{mm}$, gemstone carat equivalence of 0.50 ct - 1.00 ct, and earring style Stud / Solitaire.