The 59FIFTY is the hat New Era is famous for. It is a fitted cap coming in many sizes for a perfect fit. There is roughly a centimeter difference between each size so you really should measure your head before you buy a 59FIFTY style. The crown of the hat has what is called a constructed crown. A constructed crown simply means that New Era has reinforced the front panels of the cap for a more rigid feel so the 59FIFTY keeps its shape. The brim of the hat comes out flat.  You can curve the brim over time and get a different look. but more and more people are keeping the brim flat throughout the life of the cap for a unique look that the 59FIFTY is famous for.