The term 'FILLS A FLAT' is a job description for a tire technician. Tire technicians are responsible for repairing and replacing tires on vehicles, which includes filling a flat tire with air or sealant. They also inspect tires for wear and tear, and check the pressure of each tire to ensure that it is at the correct level. Tire technicians must be knowledgeable about the different types of tires and their uses, as well as the tools and techniques used to repair and replace them.