Start your high performance, high compression or stroker engines easily with these compression release valves. These little gadgets make starting the biggest monsters effortless. No longer will it be necessary to install heavy duty starters or high amp batteries and these valves are a must for individuals who prefer to kick start their bike. Simply depress the valves to partially release compression and once the engine roars to life the valves close automatically. Manufactured in the USA of aircraft quality stainless steel, these valves require a hole be drilled in the cylinder head to accommodate a 5/16-24 thread and spot faced for the crush washer. Copper crush washers included. Fits all Big Twin and Sportster models. Sold in pairs. Manufacturer