What is Air Conditioner register?

An air conditioning register, also called a vent, grille, or diffuser, is an opening in a wall, ceiling, or floor through which air flows into or out of a space. Registers are typically used to control airflow in a heating and cooling system, but can also be used for ventilation or to circulate fresh air. Registers may be adjustable, allowing the user to control the amount of airflow, or fixed, providing a constant flow of air. They may also be designed to blend into the surrounding décor.