oakley flak

I own 2x M Frame, 1x Whisker, and lots'a extra lenses. I need to buy an RX set of Flak sunglasses for this Summer. But I'm confused: Flak Jacket Flak 2.0 Flak 2.0 XL I can't seem to find a comparison matrix/chart anywhere that breaks down the differences? Is it just appearance? Flak Jacket...