The HK2000 Fresh Air & Economizer Panel provides Economical, and Intelligent Control of Residential and Light Commercial Cooling Systems, using the included Dry Bulb Mode sensor, or an optional Enthalpy Control. The HK2000 can control up to three (3) 24 vac dampers. Outside Air, Return Air, and Exhaust Air. The HK2000 also provides an adjustable Time Based Fresh Air Cycling Schedule, to purge your home or office of stale air and odors. Using the HK2000 can cut your cooling bills and help to cure a sick home or building. The HK2000 is suitable for all new construction and most retro-fit applications.