ELI5: Explain Like I'm 5

Helmet cover

A helmet cover is like a hat for your head helmet. It is a piece of fabric that goes over your helmet to make it more colorful or to help keep your head dry. It is like when you put a toy cover on your stuffed animal, but for your head helmet. You can take it on or off like you take off your socks. It is a fun way to make your helmet look cool and different from others.