High Carbon Quality: Carbon material used activated charcoal, and the carbon layer thickness is 1.5", delivering 100% filtered airflow. Outside used steel plate with mesh with changeable pre-filter with lanyard. ●The predominance of micro pores ensures effective removal of low molecular weight contaminants. Eliminates Odors: This 4 Inch air carbon filter will eliminates odors created from indoor plant grow operations to bathrooms, basements and kitchens. This item will bring you exceptional odor control for better privacy. Long Life-Span: 1.5" thick carbon layer will work for higher absorption and performance, reversible filter flange and base will let the filter last for longer life. Usage: Item can be used as intake or exhaust filter in a all kinds of setups with 4" inch inline fan and duct fans, inline and exhaust fans, air exchange fans, ventilation ducts, and other accessories in a grow tent or indoor greenhouse growth. Package Includes: Carbon Filter; Changeable Pre-filter; Carbon Filter Belts.