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 X-Large:Length:55.11 in,Breast:40.15 in,Waist:29.52(max) in
Asian XX-Large:Length:55.11 in,Breast:44.09 in,Waist:35.43(max) in
Asian XXX-Large:Length:55.11 in,Breast:48.81 in,Waist:37.40(max) in
Asian XXXX-Large:Length:55.11 in,Breast:52.75 in,Waist:39.37(max) in
Asian XXXXX-Large:Length:55.11 in,Breast:56.69 in,Waist:41.73(max) in
Asian 6X Plus:Length:55.11 in,Breast:60.62 in,Waist:45.27(max) 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:
  XL:Length=55.11in,Breast=40.15in,Waist=29.52in
  2XL:Length=55.11in,Breast=44.09in,Waist=35.43in
  3XL:Length=55.11in,Breast=48.81in,Waist=37.40in
  4XL:Length=55.11in,Breast=52.75in,Waist=39.37in
  5XL:Length=55.11in,Breast=56.69in,Waist=41.73in
  6XL:Length=55.11in,Breast=60.62in,Waist=45.27in
  
• Fabric:ice silk(100% polyester)
• High waist design make more slender body curve
• Ice silk fabrics drape super good,fine workmanship,more stylish

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.