SKU 609 - 1,000 Chrome Plated ABS Valve Stem Caps with N2 Insert - 10mm Complete with Silicone Inner Seal Includes Extra Inner Silicone Seal for a more secure fit. Durable ABS Plastic construction. When used on aluminum valve stems apply a thin layer of dialectic grease to inhibit corrosion on the valve stem which could damage the in tire TPMS system chrome finish larger than standard caps