I love these for hot yoga. They keep me relatively cool and they dry fast when you hang them up. I usually wear a women's size M to L (8-10, 36C)  top and these fit me perfect. I wouldn't recommend them for anyone who is larger because they will be snug. It's unfortunate that they only come in One Size Fits All, because that just isn't true. However, they are made to drape loosely so if you are smaller than I am it should still fit you too.  They are a soft, thin swimsuit-like material but just to warn you, they come with large itchy tags sewn in to the side. If you are careful, you can cut them out without damaging the tank and won't feel the tags at all anymore. I wash these in the gentle cycle with a little detergent and white vinegar and hang them up to dry. They have never faded, bled or started to smell. I really like all of Onzie's clothes for hot yoga but it bothers me that they don't make any sizes (tops or bottoms) for women any larger than me.