HQRP 2-Pack Washable Filter compatible with Eureka Optima 431 431BX 431F 437AZ 431DX 431F 437AZ 437 Lightweight Vacuums plus Coaster HQRP&reg; 2 Filters plus HQRP&reg; Coaster; This filter is HEPA filtration class H12 and retains 99.97% of particles down to 0.3 micron. HQRP filters are washable and reusable! 100% Compatible with Original filter; 2 weeks DOA replacement warranty!