Counteracts premium EPDM Rubber snap-in valve stems are made from the highest quality materials to meet any automotive need. The EPDM compound is tested and tough to withstand any weather condition and avoid corrosion. Each valve stem has a brass thread to ensure a tight valve cap seal and eliminate valve leakage. When mounting the valve stem, it is necessary to use a certified rubber mounting compound to achieve a proper airtight seal. Counteract does have a Europaste mounting formula for tires that aids well in this application.