Abstract: The invention relates to a grille or grating for fitting in the floor or wall or ceiling of an enclosed space, for example at the terminal outlet of a ventilating or air conditioning duct, and provides a grille which comprises a plurality of blades of generally rectangular cross-section which are press-fitted into spacedly arranged slots of a series of mullions. Said blades are received in said slots by spring clips located one in each slot and which clips have projections which lock said clips in said slots when the blades are inserted and reverse barbs which prevent withdrawal of said blades.