A new, perfectly oiled ProFilter Air Filter provides maximum airflow and increased horsepower. Ready-to-Use Air Filters are constructed of dual-layer, reticulated foam. Reticulation is a process that opens up the foam cells, allowing for increased air flow and horsepower. The dual foam layers differ in foam pore size – the innermost foam consists of a denser foam to catch fine particles of sand and powder, whereas the outermost foam is constructed of a more open pore matrix allowing for filtration of larger micron dirt particles. The open porosity of the outer foam also helps the air filter resist plugging. Air filter seams are welded with industrial strength adhesive and all filters come with a rubber grommet to help secure the filter in place to the cage, eliminating tearing and keeping the structural integrity of the filter intact. When you get ready to change your filter, choose ProFilter.