Amsoil EA synthetic nanofiber oil filters are the absolute best oil filter that money can buy. Made with advanced nanofiber technology, these filters offer an efficiency rating of 98.7 percent at 15 microns. Amsoil EaO filters are recommended for 25,000 mile drain intervals in normal service and 15,000 mile drain intervals in severe service. Amsoil Ea15K filters are designed for 15,000 mile drain intervals in both regular and severe service