United Kingdom Size Extra Small to US: Snug / 47mm

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.

US: Snug / 47mm: Corresponds to a nominal width of 47 $\text{mm}$ (1.85 $\text{in}$), length of 170 $\text{mm}$ (6.69 $\text{in}$), average structural girth of 94 $\text{mm}$ (3.7 $\text{in}$), and fit category Snug / Slim.