Compatibility: Compatible with replacement Therapure TPP240F filters and fits TPP230H and TPP240D air purifiers. Air Quality Improvement: Filtration is rated H13 and removes up to 99.97% of airborne particles as small as 0.3 microns in size including dust, smoke, pollen, pet hair and dander, mold spores and dust mites. 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 (6) months under normal conditions, and more often under harsh air conditions. Package contains two (2) replacement filters. Approximate Measurements: Each filter measures 23 x 4 x 2 inches. Replacement filter compatible with Therapure TPP240F air purifier filter. Engineered to fit Therapure TPP240 air purifier. Foam gasket seal directs airflow through the filter and prevents air from escaping around sides. Recommended to replace filter every six (6) months for maximum efficiency, or more often in harsh environments. Contains one (1) replacement filter. Approximate Dimensions: 23 x 4 x 2 inches.