The Topo Designs Mountain Plaid Shirt takes its western roots and builds them into a 5. 5oz organic cotton twill flannel, light enough to wear alone and warm enough to layer under a jacket when temperatures drop. Oversized BDU button closures at the front and cuffs give it a workwear edge, and dual flap chest pockets add function without adding bulk. It's a relaxed fit built for all-day comfort, on or off the trail.