Watch a pair of COMP Cams® Hydraulic Roller Lifters get manufactured from beginning to end. The completed lifter may appear simple from the outside, but this video shows the amount of engineering that it takes to build the finest hydraulic roller lifter available today. As a result of that extensive design and testing effort, COMP Cams® Hydraulic Roller Lifters are used by the top engine builders today in the best performance racing engines.