The Tjernlund Register Booster Fan is a duct-mounted fan designed to boost airflow through heating and cooling registers. It features a steel housing with baked enamel finish, thermally protected PSC motor, and plug-in cord. The fan has 3 speed settings, moves up to 300 CFM of air, and measures 14"L x 8-1/2"W x 11"H. It can be used to increase airflow to underheated or undercooled rooms. The booster fan requires 120V power and is ETL listed. It comes with mounting brackets and installation hardware. This register booster fan provides an easy way to balance temperatures in different rooms.