The Whirlpool Dryer Control Board Part # 3978994 Rev Rel is a main control board designed for Whirlpool dryers. This blue control board is a genuine replacement part manufactured by Whirlpool in the United States. It is specifically designed to fit the Whirlpool 3978994 model, providing essential control functions for your dryer. With this control board, you can ensure that your Whirlpool dryer continues to operate efficiently and effectively.