Grilles are installed on circular ducts by tapping and are designed for supply and removal of air in rooms for various purposes. GRD-K single row grilles are a steel housing with individually adjustable aluminium louvres for changing the direction and/or characteristics of the supply air stream. The louvres are mounted in plastic bushings which facilitate their rotation during adjustment. The louvres are positioned perpendicular to the duct axis. The grilles are equipped with a flow regulator and are used to supply air when one or more grilles are installed and the network needs to be adjusted. The grilles are powder coated in grey (RAL 7047). Customised products can be painted in any RAL colour.