Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for select models: features include internal and external bracing, dedicated embossed forgings for weight reduction, specialized processes such as internal milling the internal struts, along with dedicated accumulator groove and forged side relief, Includes Pins, pin fitment, lock and rings, Made in the U.S.A.