I'm 5'5", 150lbs and wear a 38B bra. I initially bought size XL based on the size chart, but it was a bit too snug on me. I wore it from morning to night and didn't have much difficulty moving or breathing, though it was a bit constricting. I then bought the XXL and it was much more comfortable while still providing the same level of chest flatness as the XL. It fits like a tank top and doesn't ride up into my armpits. Even though I'm only a B-cup, I was impressed by how much it flattened my chest while still being breathable and flexible.My only gripe is the lack of color choices. I would've preferred solid color options like white, black, and nude to match any top.Overall, I'd recommend it! Disclosure: I only use this binder for cosplay, so I'm not sure how comfortable it would be to wear it regularly.