Richardson 511 Wool Blend Flatbill Trucker Caps A wool blend front with a nylon mesh back give this classic-looking cap some modern style. Shape: HiPro Fabric: Acrylic-Acrylic-Wool Blend/Polyester Mesh Visor: Flat Sweatband: Cotton Fit: Adjustable Snapback Size: One Size Fits Most SOLID COLORS: Undervisor is cap color. TRI-COLORS: First color is crown front panels and eyelets. Second color is crown back mesh panels and backstrap. Third color is visor and button. SPLIT COLORS: First color is crown front panels, eyelets, visor, undervisor, backstrap, and button. Second color is crown back mesh panels.