Two types of systems used to protect our compounds:Passive systems: Paraffinic and Microcrystalline WaxesBlooms to the surface of the compound and forms a physical barrierPrevents oxygen and ozone from reaching the surface of the compoundOnly works while tires are in storageActive systems: Antioxidants and AntiozonantsReacts with the oxygen and ozone before they can break the polymer moleculeWorks while tires are in service