Mr. Gasket Air Cleaner Adapter and Riser Kit is a four piece kit which includes two air cleaner adapters to adapt 5-1/8" neck (4 or 2 bbl carb) air cleaners to 3" and 2-5/8" 2 barrel carbuertor necks. It also includes two air cleaner risers that combine for three height adjustments, 1/2", 1" and 1-1/2" to help space air cleaner upward to clear throttle or transmissiobn linkage. They end air cleaner fit problems when you change carburetors with air cleaner adapter ring. This adapter is molded from a high-impact, heat resistant material for durability.