Open-mounted diffusers for supply and exhaust air are designed for rooms where a large amount of air is required without perceptible draft. The airflow angle of the device can be adjusted according to the needs of the area and changes in its layout. The low design height of the diffusers saves space and the adjustment of the products is clear and precise. Due to the structure of the diffusers and the surface treatment, the surface of the products is particularly easy to clean.