US: 3XL (54–56) to United Kingdom Size 38–40

US: 3XL (54–56): Corresponds to a chest width of 137.2–142.2 $\text{cm}$ (54–56 $\text{in}$), neck collar girth of 49.5 $\text{cm}$ (19.5 $\text{in}$), sleeve length of 96.5 $\text{cm}$ (38 $\text{in}$), and fit style Big & Tall Fit.

United Kingdom Size 38–40: Corresponds to a chest width of 96.5–101.6 $\text{cm}$ (38–40 $\text{in}$), neck collar girth of 39.4 $\text{cm}$ (15.5 $\text{in}$), sleeve length of 86.4 $\text{cm}$ (34 $\text{in}$), and fit style Classic Regular Fit.