The marking of the baseball cap under the helmet will not allow the head guard to sit exactly on top of the job. The Bicycle Helmet Safety Institute, a non-profit organization for bicycle helmet safety, warns that hats and visors violate helmet compliance and safety. The helmet is designed to fit tightly into the skull, with nothing between your head and the inside of the helmet. You can use Valucap Foam Trucker Cap style #VC700 is very helpful.