2XU zippered athletic wear. It's stretchy and fits the body well. It has non-slip material on the shoulders to prevent a backpack from slipping. I used it for trail running, but I think it can also be used for running, triathlon, road biking, etc. It has been used to a certain extent, please check the photos. Please understand that this is a used item and only purchase if you agree to no returns/no refunds.