Compatibility: Compatible with Shark Air Purifier 6 Series HE6FKPET filters. Engineered to fit Shark model numbers HE601 and HE602. Air Quality Improvement: Filtration is rated H13 and removes up to 99.97% of airborne particles as small as 0.3 microns in size. Airtight Seal: Foam gasket seal for high performance filtration directs air through the filter and keeps air from escaping around the sides. Maintenance: Recommended to change this filter once every six-to-twelve (6-12) months under normal conditions, and more often under harsh air conditions. Package contains one (1) replacement filter. Approximate Measurements: 24.75 x 15.1 x 1.6 inches. Filter-Monster branded replacement replacement filter compatible with Shark Air Purifier 6 HE6FKBAS filters. This filter is compatible with model numbers HE601 and HE602. To maintain peak performance and fresh air in your home it is recommended to replace every six to twelve (6-12) months or more often depending on air quality and environmental factors.