The Twin Air-Air Filter is designed with high quality materials and superior construction that delivers unbeatable performance and protection and will make the Twin Air- Air Filter the hands down choice of more world & national champions than all other filters combined. The Twin Air-Air Filter has two layers of foam the first layer of foam is open pore foam that catches airborne dirt, grime and sand and the second layer of foam traps the smallest of particles while ensuring maximum air passage. The Twin Air- Air Filter will give you the performance and durability that you want your machine to have during all types of conditions you will take it through.