4Pcs/Set Universal Car Skull Style Antirust Copper Core Motorcycle Bike Car Wheel Tyre Tires Valve Stem Caps//Features: 1. High quality sealing ring inside the valve caps, to prevent the flat tire. 2. Specially designed to replace the plastic caps. Easy to install and safe to use 3. Dust proof: To ensure stable tire pressure by protecting the valve core from corrosion due to direct contact with clay, water and snow. 4. To protect and decorate the valve caps with lovely color, and personalized design. Why do we use valve caps? 1. Ensure our traffic safety. Ensure stable tire pressure by protecting the valve core from corrosion due to direct contact with clay, water and snow. 2. Decorate our vehicles! Show our personality! Replace our old valve caps with the new personalized design. 3. Protect the valve core and prolong its life-span. How to maintain the valve caps? To avoid the valve caps natural oxidation and corrosion, we should maintain the valve caps with the following methods: 1. Avoid long time exposure of the valve caps to water or snow. 2. To unscrew and clean the valve caps, and to check the tire pressure on a regular basis, say 2-4 weeks/once, so as to prevent the oxidation of the valve cap threads and ensure the tire pressure normal. Notes: 1. Put the valve caps away from kids to avoid eating. 2. If you forget unscrewing the valve caps for a long time, it may hard to unscrew. There are two ways to help you: ONE: To heat the valve cap with a lighter below 50 degree and then screw it with pliers. SECOND: To add some oil (edible oil is ok) into the valve cap and then screw it several minutes later. Package: 4Pcs/Set * Skull Valve Caps