These are my personal favorite leggings; I wear a pair almost every day. They are very stretchy and comfortable, great for lounging around or exercising, either way. I've worn them doing yoga myself, and they allow for full range of motion without binding at any seams. I am a larger-bootied lady and I do fit into the "one size", though I must admit in some of my pairs I've ended up with some holes near the threads eventually. It's worth it though, and other than that they've lasted forever. Those holes are the only reason I've every had to get rid of a pair, so if you're any amount less bootiliscious than me you'll have these for years to come. 

Due to the fabric being tie-dye there may be some variation in color from the pictures shown.