Speedmaster™ piston rings are designed to stand up to the rigor of racing and high-performance street use, while providing a long lasting life. Speedmaster™ piston rings feature: Plasma-moly coated, barrel-shaped, ductile iron top rings that seal against blow-by when the piston rocks in its bore; tapered secondary rings that seal against the oil control ring’s upper surface for excellent oil control; and 3-piece oil rings with stainless steel expanders that provide accurate tension without the loss of any horsepower.