An enlisted sailor in the pay grade E-3, equivalent to a Marine lance corporal. The non-rated grades wear slash marks on the upper left arm only. Seaman is a “deck force” rate and is indicated with white slashes. Airman is an “aviation” rate and is indicated with green slashes. Fireman is a mechanical rate and is indicated with red slashes. Constructionman is for members of Navy Construction Battalions (Sea Bees) and the slashes are blue.