My bra size is typically 36B and the medium fits me perfectly on the loosest hook. The fabric is soft, stretchy, and light. It's tag-less, which is nice. It's so comfy! I wanted something lightweight to wear in the summer (it gets HOT and humid where I live) and this is perfect.
I find it to be supportive for my breast size, but it doesn't do too much to hide your nipples. Overall, great product and I plan on buying more in other colors.