The HVAC Air Filter 20x30x1 is a pleated filter designed for use in air conditioners and furnaces. Made by Arm and Hammer, this filter features electrostatic filtration technology to capture airborne particles. With a filter life of 3 months, this white filter is constructed with a synthetic filter media and an aluminum filter frame. Manufactured in the United States, this unit is perfect for maintaining indoor air quality in your home. it's a 4 pack.