US: Maximum / 69mm to United Kingdom Size Extra Small

US: Maximum / 69mm: Corresponds to a nominal width of 69 $\text{mm}$ (2.72 $\text{in}$), length of 220 $\text{mm}$ (8.66 $\text{in}$), average structural girth of 138 $\text{mm}$ (5.43 $\text{in}$), and fit category Maximum Bariatric / Ultra Wide.

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.