FRS160 - M FR Classic Twill Shirt Carhartt's flame-resistant twill shirt with pocket flaps works as hard as you do. ORIGINAL FIT • 7-ounce, FR twill: 88% cotton/12% high-tenacity nylon • Button-down collar with button closure • FR melamine buttons throughout • Two chest pockets with flaps and button closures • Extended sleeve plackets with two-button adjustable cuffs • Triple-stitched main seams for durability • Carhartt FR label sewn on left pocket; NFPA 2112/CAT 2 label sewn on sleeve placket • Meets the performance requirements of NFPA 70E and is UL® Classified to NFPA 2112