Our Stem Covers comes in stylish, unique and lustrous design.will give your car a unique eye-catching look and will make you stand out from the crowd. Warm Notice: To prevent the metal valve cap from fusing with the tire valve stem, please apply grease lubricant onto the threading of the valve stem prior to installation. Aluminum valve caps would be locked if they stay in acid or alkaline liquid environment for a long time, please loosen them at least once per month.