Pro 5R Media: This filter features Pro 5R oiled 5-layer progressively finer mesh cotton gauze media for maximum performance. The progressive layering of media allows the filter to flow at high levels even when dirty. Rounded Open Pleats: aFe performance air filters use a rounded, evenly spaced pleat design which produces more usable filter surface area for increased flow and greater dust holding capacity. Progressive Bump Seal: This pliable sealing surface conforms to even the most uneven filter housing. This design eliminates the use of gaskets or sealants. The soft urethane construction always goes back to its original form so you will never compress the bump seal. This makes for a perfect filter fit and sealing surface every time .Full Polyurethane Frame: aFe Power performance air filters are constructed using full 360 degree polyurethane frame. This construction allows for a proper factory style fit with excellent filter strength.