Hat Sizes and styles
There are thousands of different hats available in the market today and you have many choices.
Adjustable hats have a adjusting mechanism in the back of the hat. Least expensive is a plastic strip with holes and a tab for adjustment
Most common is the Velcro strap in the back which adjust the size
Another common style uses a small buckle strap for adjustment
Flex Fit type hats have a elastic band built into the hat and are generally offered in two sizes S-M or L-XL. These hats will be closed in the back and not have the traditional opening found on adjustable hats
The least common type hat and the most precise is the fitted hat which is available in limited styles and limited colors and are made in specific hat sizes. These hats are most widely used in baseball and are also popular with umpires.