This is a vest designed to be worn over your clothes during Yosa, Lululemon time, to help you sweat even more. The amount of sweat you produce is significantly different when wearing this vest compared to just wearing your workout clothes alone. You can also wear it in the winter when it's cold. For anyone looking for a good deal. I had several vests, so I didn't wear this one very often, and it's in great condition with no tears or stains. Thank you for looking.