18 x 24 x 2 MERV 8 Pleated Filter. Case of 12 filters. Actual Dimensions 17.5 x 23.5 x 1.75" 14 Pleats per Lineal Foot. The electrostatically charged 100 synthetic graduated density media is continuously bonded to a 30 gauge galvanized corrosion resistant expanded metal support grid with an effective open area of 96. The media is resistant to a wide range of chemicals, does not absorb moisture and will not support microbial growth.The controlled pleat spacing maximizes surface area and dust holding capacity and is bonded to the enclosure frame to prevent dust bypass.The enclosure frame is constructed of high wet strength moisture resistant beverage board. The diagonal support members of the frame are bonded to the entering and exiting apexes of each pleat to prevent pleat collapse and filter bowing.