The optional sizes are Asian sizes.Asian size is two sizes smaller than US or UK size,so you'd better buy 2 sizes up.The best way is viewing these detailded size data carefully and select the right size according to you measurement.
Asian XX-Large:Length:55.12 in,Breast:46.06 in,Waist:23.62-46.06 in
Asian XXX-Large:Length:56.30 in,Breast:50.00 in,Waist:27.56-50.00 in
Asian XXXX-Large:Length:56.30 in,Breast:53.94 in,Waist:31.50-53.94 in
Asian XXXXX-Large:Length:56.30 in,Breast:57.87 in,Waist:35.43-57.87 in

• The optional sizes are Asian sizes.Asian size is two sizes smaller than US or UK size,so you'd better buy 2 sizes up.
• The best way is viewing these detailed size data and choose your right size:
  2XL:Length=55.12in,Breast=46.06in,Waist=23.62-46.06in
  3XL:Length=56.30in,Breast=50.00in,Waist=27.56-50.00in
  4XL:Length=56.30in,Breast=53.94in,Waist=31.50-53.94in
  5XL:Length=56.30in,Breast=57.87in,Waist=35.43-57.87in
  
• Fabric:ice silk(100% polyester)
• High waist design make more slender body curve
• Strings at the back can adjust tight or loose

The optional sizes are Asian sizes.Asian size is two sizes smaller than US or UK size,so you'd better buy 2 sizes up.