HQRP Washable Post Motor Filter for Bissell Power Trak 6390/3910 series 3910-6/39106 / 6390W Cyclonic Momentum Bagless Vacuum Coaster HQRP&reg; H11 Post-motor media filter plus HQRP&reg; Coaster; HQRP filter is washable and reusable! This filter is H11 filtration class and retains 95% of particles down to 0.3 micron. Dimensions: 9.25" x 2 5/8" x 7/16". Recommend replacing your vacuum filters every 3 to 6 months Compatible with Original filter; 2 weeks DOA replacement warranty!