K&:N in connection diameter variable universal air filters are supplied including adapter rings with which the connection diameter can be varied in 3 sizes. The flange of these filters is made of ultra-strong flexible rubber which absorbs vibrations excellently and ensures a safe and sound assembly. K&:N universal air filters are washable and reusable. Specifications: Product type: Round conical universal air filter Version: Round conical Diameter base plate: 6 inch (152 mm) Diameter top plate: 4.75 inch (121 mm) Connection diameter 1: 4 inch (102 mm) Connection diameter 2: 3.5 inch (89 mm) Connection diameter 3: 3 inch (76 mm) Flange length: 1.125 inch (29 mm) Flange type: Centered Height: 9.5 inches (241 mm) Filter material: Cotton Material: Metal / Rubber Finish: Chrome Color red Guarantee : 2 years