Earmuffs
An earmuff is a device composed of a headband and two circumaural cups usually made of plastic.

The ear cup encloses the outer ear and seals against the side of the head with a cushion. Some earmuffs are designed to fit on hard hats.
Adjust the headband so that it fits comfortably on your head. Make sure that the cushions exert even pressure around the ears while pulling your hair back and out from beneath the cushions to ensure proper seal. The earmuffs should fully enclose the ears.
Earmuff cushions should be periodically wiped or washed clean.