15 Wool 82 Acrylic 3 Spandex, Structured, Firm Front Panel, The Flexible Fit. 6 Panel Flexible Fitted Cap Seamed Front Panel with Full Buckram 6 Sewn Eyelets Pro Stitch on Crown 8 Rows Stitching on Visor Matching Fabric Undervisor OTTO FLEX Stretchable Sweatband - A snug, flexible fit with antibacterial, anti-odor and moisture wicking properties U.S. Patent 6,347,410