Uni Multi-Stage Competition Air Filter NU-8517STUnsurpassed in airflow, dirt stopping and overall performance Fits in stock air box exactly like OEM filter Traps dirt and dust in 2 layers of foam The large pore, pre filter captures the bigger particles The small pore, inner filter prevents any engine wrecking grit from reaching the cylinder Features the Ultra Seal grease groove on the sealing surface Made in the U. S. A