Genuine Hunter F1821H13 replacement air purifier filter. Fits Hunter air purifier model HT1821. 

• True HEPA filtration removes up to 99.97% of airborne particles as small as 0.3 microns in size including smoke, dust, pollen, pet hair and dander, mold spores and dust mites
• Recommended to replace every 12 months for maximum efficiency, or more often depending on air quality & environmental factors
• Package contains 1 replacement filter
• Dimensions: 10-3/10 x 5-1/10 x 1-3/5 inches

Fits