16pcs GM Chevrolet 5.3L 6.0L Valve Lifters Active Fuel Management AFM DODFeatures: 1)The hydraulic roller lifter is designed to compensate for this small tolerance, so that the valve train operates under the condition of zero clearance, the operation is quieter, the engine life is longer, and there is no need to adjust the valve clearance regularly. 2)All our parts are strictly tested for quality and manufactured to improve performance. These steps are to control the quality of components that can work for a long time.