The DVK Dryer Exhaust Fan with Mounted Pressure Switch is designed to enhance the drying efficiency of residential, commercial, and industrial clothes dryers. The pressure switch in the DVK100B-PM Dryer Booster Fan Kit is pre-wired and factory mounted to the DVK100B dryer booster fan. The PST120V is an airflow proving switch. It initiates the booster fan when it senses positive air pressure from an operating dryer, and the pressure switch has an integral timer with a 10 minute ON and 15 second OFF cycle, enabling the fan to restart as long as the dryer is operating. The DVK dryer exhaust fan features a quiet and efficient backward curved impeller that is capable of overcoming long duct runs. The an in-line configuration simplifies the installation of the fan. Features: External rotor motor for quiet and efficient operation. Backward curved impeller to overcome long duct runs. In-line construction to reduce lint build-up. High temperature construction: 60 C/140 F. Thermal overload protection. Automatic reset.