A built in flexible rim makes this cap a snug fit for a range of sizes but is available in different base sizes anyway as well as colors.
On each side, tucked away neatly in a pocket, is a tethered ear plug. They can be pulled down and placed in each ear independently and then removed and returned with a simple touch of a button. Earplugs are a bit overkill for Airsoft but as an export-only item they make a welcome addition for a day on the range shooting real steel.
A neat baseball cap with earplugs you can not loose, the cap also has Velcro pads on the front, back and sides for adding your own aftermarket accoutrements (not included).