The CF8 rough finish stainless steel (equivalent to type 304) body, cover and closure plug of this unit is designed to prevent sewer gases from entering through the drain in buildings that process corrosive liquids while maintaining high levels of sanitation (ie. chemical laboratories, dairies, breweries, and atomic energy and bottling plants). The 8-1/2” (215) diam. solid scoriated top can easily be adjusted to meet the level of surrounding flooring.