Charcoal Carbon Filters for ductless ventilation. Made from high quality materials to provide longest usage possible. Includes one set of (2) charcoal filters, which lasts 6 months based on normal usage. For use with the following Model Numbers: 668ICS900, 63190, 63175, 63175S , 63190S , 63ISS75, 63ISS90, 668WRC75, 668WRC90, 668WRCS75, 668WRCS90, & new version of 668A750 & 668AS750 (with lights in front).