HQRP Post Motor Media Filter + H12 Circular Filter for Bissell CleanView Helix Deluxe Vacuum 21K3 series 21K31 21K32 21K35 Coaster HQRP&reg; H11 Post-motor media Filter plus H12 Circular Filter plus HQRP&reg; Coaster; The post motor filter is H11 filtration class and retains 95% of particles down to 0.3 micron. Dimensions: 7.25" X 2.25" X 0.5". The circular PP compound filter is H12 filtration class and retains 99.97% of particles down to 0.3 micron. Dimensions: up diameter: 3.73"; down diameter: 3.37"; height: 2.62"; Recommend replacing your vacuum filters every 3 to 6 months. Compatible with Original filter; 2 weeks DOA replacement warranty!