This latest version of the Screamin’ Eagle High-Capacity Tappet incorporates a special heat treatment on the bearing needles and axle. In addition to the already proven, 25% larger, high capacity needle bearings, this new heat treat technology increases material hardness and compressive strength, ultimately enabling the tappet to withstand the grueling engine speeds and high valve lift found in many performance engine configurations. The newest technology is identified with a laser-etched “SE” on the axle of the tappet (shown in product image).