aFe MagnumFLOW Air Filters Round Racing PDS A/F TOP Racer 14D x 4H (PDS)aFe MagnumFLOW Air Filters Round Racing PDS A F TOP Racer 14D x 4H (PDS) 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