A-B1595191-AI FILTER-AIR CLEANER FOAMOne New Aftermarket Replacement Air Cleaner Foam Pre Filter Fits Briggs & Fits Stratton Small Engines This foam pre filter (air cleaner foam) fits over the primary air cleaner cartridge to provide an additional layer of protection, trapping dirt and debris before they reach the main filter and carburetor. Regular replacement of this foam pre filter helps protect the engine from airborne particles and extends the service life of the primary air filter