MERV Rated MERV 11 to MERV 15 available in BOX or Header style for Variable Air Volume Systems in 4”, 6” and 12” depths. Medium to high efficiency extended surface deep pleated rigid box filters are manufactured from a new generation range of inherently anti-microbial, high lofted synthetic fiber filter media or micro – fine glass fiber filter media. It is capable of removing contaminants from the air stream and is an ideal fine filter for HVAC systems.