Fabulous, a vest can make a huge difference to your comfort, wicking fabrics need to be in contact with your body, in order for them to take the moisture off the skin. This vest moves moisture with great effectiveness, leaving you nice and dry. It is a good way for those who do not like stepping out figure hugging sportswear to get a layer close to the body, because a looser fitting garment can be worn over the top. A medium equates to a size 12.