Using an ear "cup" inside the helmet creates an air gap sound barrier that reduces outside noise. This is especially important when using radios since it isolates radio sound in the helmet. The ear cup has a soft foam ring around its hard plastic shell so it is comfortable to wear inside the helmet. Ear cups are velcro backed and the same shape as the removable flat ear cover inside a VESTA helmet so it is an easy swap out. They do not change the fit of the helmet cheek pad and are sold as a pair.