FABRIC TECH: 57% polyester/40% nylon/3% CDPET You don't have to be an old timer to have an appreciation for the classics. The Simms Big Sky Shirt - Short Sleeve is a western-styled, modern take on a classic look. New-fangled tech like plush wicking fabric, UPF 50+ sun protection, and a vented mesh-lined back panel ensure that this shirt is ready for the water or for a leisurely trip to the fly shop to chat about who's catching what, where