United Kingdom Size Original to US: Slim / 49mm

United Kingdom Size Original: Corresponds to a nominal width of 54 $\text{mm}$ (2.13 $\text{in}$), length of 191 $\text{mm}$ (7.52 $\text{in}$), average structural girth of 108 $\text{mm}$ (4.25 $\text{in}$), and fit category Standard / Original Universal.

US: Slim / 49mm: Corresponds to a nominal width of 49 $\text{mm}$ (1.93 $\text{in}$), length of 175 $\text{mm}$ (6.89 $\text{in}$), average structural girth of 98 $\text{mm}$ (3.86 $\text{in}$), and fit category Snug / Close.