US: Large / 57mm to United Kingdom Size Extra Small

US: Large / 57mm: Corresponds to a nominal width of 57 $\text{mm}$ (2.24 $\text{in}$), length of 200 $\text{mm}$ (7.87 $\text{in}$), average structural girth of 114 $\text{mm}$ (4.49 $\text{in}$), and fit category Large / Roomy.

United Kingdom Size Extra Small: Corresponds to a nominal width of 45 $\text{mm}$ (1.77 $\text{in}$), length of 160 $\text{mm}$ (6.3 $\text{in}$), average structural girth of 90 $\text{mm}$ (3.54 $\text{in}$), and fit category Extra Small / Pediatric / Snug.