I've already sent them back. They didn't even make it through one yoga class. I had to rip them off. The material is all wrong - they don't cling to your feet, so they slide around on your foot and start slipping off. They actually made me less stable. I felt like I was going to trip. The toes were too long for me, so they didn't even fit properly. I wear a size 7-8, depending on the type of shoe, so I would have expected a small/medium to fit snugly, but they don't. Also, in a really warm studio (not even Bikram, but just hot from all the body heat), they would be horribly uncomfortable. They'd need to be way thinner and clingier. I think I'm just going to try to find a better mat.