Citadel Shirt S - Gravel. Our new Citadel shirt never met a hot day it couldn't handle. And its built-in UPF 50+ protection proves it. What's even cooler is that its yarn dye plaid fabric has been treated with a wicking finish to quickly absorb sweat and moisture. Classically styled to get you in and out of any situation, with rolled-cuff short sleeves and double chest pockets with Velcro closures.