100% microfiber polyester fishing shirt.  50+ UPF Sun Protection.  Anti-microbial and wrinkle resistant.  This is the good stuff.  Great looking shirt that handles routine wear, and cleans easily to remove pluff mud, fish slime, mayo from your sandwich on a water lunch, and even fish poop (ask me how I know) - pretty much anything you can throw at it.  I've put these through the ringer, and they keep on ticking.  Great shirt for outdoor use, and my favorite for saltwater fishing.  Fits true to size.