The T.O.P. Racer from aFe is a patented design by aFe which allows air flow from the side and top of the filter in a single piece design. The T.O.P. Racer filter is uses a one-piece design that eliminates leaks and sealing failure under changing pressures. Air flows in from both top and side sections. This unit uses the PRO Dry S filter media which is constructed of 2-layers of synthetic media that requires no oils for cleaning for maximum convenience. The T.O.P Racer filter is washable and reusable and has a 100% satisfaction guarantee.