Twin Air 152611 Foam Outer Cover for Stock Filter Fits: Yamaha 350 Bruin/4WD 04-06, 350 Grizzly 07-13, 400 Kodiak 03-06, 400 Grizzly 07-08, 450 Kodiak 2/4WD 03-06, 450 Wolverine/4X4 06-10, 450 Grizzly 07-13 Twin Air filter's design, high quality materials and superior construction deliver unbeatable performance and protection, designed to increase airflow while ensuring the highest level of protection from dirt/dust Dual foam design: Coarse open-pore foam catches airborne dirt, grime and sand, fine open-pore inner foam acts as a second filter to trap the smallest particles while ensuring maximum air passage Thick, flat foam, greaseless sealing ring ensures maximum contact with your air box, while acting as a breathable gasket for increased air passage Fused outer and inner elements prevent dirt and grime from being lodged between layers while the exclusively formulated adhesive ensures glue seams will not break down