Big Accessories Flat Bill Cap - 100% Polyester 6 Panel - 2 Sizes/Choice of Black, Navy, White Fitted Flat Brim Baseball Hat. HEAVY DUTY : These flat bill hats are very durable and long lasting caps constructed of heavy-duty 100% polyester. CONSTRUCTION : The caps are constructed with 6 panels that are sewn together to form a sturdy hat thats also very stylish. STYLE : Flat bill hats are a style of baseball hat, and they are largely recognized for their flat or strait brim located on the front. DESIGN : The visor portion of a baseball cap was traditionally designed to shade a baseball player's eyes from the sun. SHAPE : The different ways to shape your bill are more of fashion statement than a functional necessity.