The circular air diffuser is generally used for heating and cooling air. Usually installed on the ceiling. The blown airflow is in the form of an attached (horizontal feed) type, and its structure is a multilayer cone shape. Because the indoor induced airflow is greater than the exhaust air volume, the blowing airflow decelerates faster. Therefore, relatively large air volume can be supplied for any area of any size, and the size of the diffusion radius changes within a given air volume range.