US: Extra Large (XL) / 60mm to United Kingdom Size Extra Small

US: Extra Large (XL) / 60mm: Corresponds to a nominal width of 60 $\text{mm}$ (2.36 $\text{in}$), length of 205 $\text{mm}$ (8.07 $\text{in}$), average structural girth of 120 $\text{mm}$ (4.72 $\text{in}$), and fit category Extra Large / Magnum Custom.

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.