This is a GU quick-drying short-sleeved T-shirt. It's a gray men's size S. It's 100% polyester with mesh sides. I tried it on after purchasing it and felt it was a bit tight, so I'm putting it up for sale. (It's been several years since I bought a T-shirt from GU, I wonder if the sizing has changed...) It's only been tried on, so please understand this before purchasing. I will fold it up small for packaging, so please be aware of that as well.