KPMI Red Viton valve stem seals are designed to have optimum fitment, allow for maximum lift, and to give maximum life. KPMI Red valve stem seals are resistant to high temperatures, petroleum products and by-products of combustion. They retain their ability to seal in situations where other materials could allow oil to enter the combustion chamber causing detonation, carbon build up and a loss of power. The Red Ones are truly the racers choice. H-D #18094-02A 4 Seals 0.562in. Guide Top Diameter 0.957in. Over All Length 0.970in. Seal o. d.