Premium valve seats for applications using steel valves, A specific combination of alloys allowed a creation of a high density, iron-based valve seat with uniform hardness, exceptional thermal qualities and high resistance to wear and recession caused by microwelding, Only by using the latest developments in powdered metal technology were we able to blend these alloys to give a seat material with the qualities required for today's engines, These seats have been tested on the track and street in high-rpm applications with leaded, unleaded, and oxygenated fuel, as well as methanol, ethanol, nitrous, and forced induction applications, Made in the U.S.A., Verify size before ordering.