AC Infinity Air Filter Box with High Efficacy Filter, 6-InchDescription Duct Filter Box: This is designed for use with inline fans to circulate fresh air and block dust and odors. It is built with 1mm thick cold rolled steel and aluminum duct flanges, which allow it to withstand extreme weather. A slide lock door enables easy access to the inner chamber, while a soft neoprene layer creates a dust free seal. High Efficacy Filter: Included is a standard filter that effectively traps particles like dust, dirt,