The square diffusers are compatible with low- and medium-pressure ventilation systems as well as A/C air supply and exhaust ducts. They can be used in steady and variable airflow systems and environmental RH up to 70%. The vane angle is fixed. As a result, the diffuser provides a horizontal air flow and it is recommended for spaces with a maximum ceiling height of 4 m. The diffuser is designed for installation on square ducts, to plenum (expansion) boxes and as ductwork termination on the suspended ceiling using screws. The diffusers are light-weight easy-to-install products and require no additional bracing of suspended ceiling panels. The diffuser vanes can be removed without detaching the entire diffuser.