TOUGHMESH(TM) FABRIC - Keep the Rays at Bay Note on sizing: It runs true to size if you want it a little loose. If you&';re a natural MEDIUM and used to performance shirt fits, a SMALL will work perfectly. "I use mine every day the sun is out, and that&&';;s nearly every damn day here in sunny Florida. I love it when I am outside on the move with some weight on my back, that&&';;s my form of mental health, but I have no interest in even having a dermatologist, let alone being on their Christmas card list. You gotta keep the rays at bay and this is how I do just that." - Jason, GORUCK CoFounder Featherweight performance ToughMesh with UPF 30+ sun protection that breathes and wicks like crazy, dries with little to no breeze, and packs down to practically nothing. The fabric is world-class ToughMesh, milled in the foothills of the Italian Alps close to where da Vinci painted The Last Supper, and it&&';;s now proven with rucks on our backs all over the world.