I’m a teenage trans boy, D cup. I bought the Small size, and I am ecstatic with the results. The black/blue combo I purchased flattens my chest about as well as a properly sized gc2b binder, but the black makes it almost impossible to see any curves. This works really well with plain black swim shorts, and it’s sturdy, easily washed, streamlined, and keeps me warm! At the beginning it was really hard to put on, though, so I now step into it and pull up, over my hips. Works much better. I recommend this to any FTM, enby, demiboy, agender, etc. person who’s looking for a good swim binder! Well worth the price, and arrived quickly!