Featuring Stainless Steel construction and a lightweight yet rugged design, it provides a bulletproof method of adjusting secondaries on all Double Pumper, HP, and Ultra HP carburetors. It allows user to pick between 1: 1 or progressive secondary ratio. Kit provides infinite adjustment of secondary throttle blades for maximum horsepower output. Features: Choose between a 1: 1 and a progressive secondary ratio Tough Stainless Steel construction for longevity, durability and control Simple installation Detailed instructions included Perfect for circle track and drag racing Compact design won't interfere with throttle linkage Includes all necessary hardwarePit Stop USA offers Holley Pro-Series Adjustable Secondary Linkage Kit for Holley Double Pumper and HP Series Carburetors 20-122 at low everyday prices. Be sure to check out all of our products from Holley Performance Products including Holley Performance Products Throttle Plate and Linkage.