The XL
The XL is ideal for surfers over 200 pounds in not-so-big-surf. Average sized riders can also utilize the generous dimensions of the XL for great low end performance in 1-3 foot waves. And cold water surfers trapped inside their 5/4 suits find a bit more buoyancy to play with when riding an XL.
Volume-wise, the Standard, Fatty and XL run from smallest to largest.