Twin Air 150911 Round Style Universal Clamp-On Dual Stage Foam Air Filter Specifications: Filter shape: round; rubber inner diameter: 63 millimeter; filter foam width diameter: 100 millimeter; filter foam length: 170 millimeter; rubber length: 15 millimeter; 185 millimeter 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 and 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