Accessory set for achieving protection class IP 54 when mounted on the ceiling. Specifically for luminaires in the Onplana D11 series. Consists of a replacement cover with an embedded seal for the ceiling finish and a sealing ring for use between the luminaire head and the surface-mounted housing. Made of sheet steel, powder-coated white. Outside diameter 435 mm. Accessories available for 10 years after the invoice date, subject to reasonable changes in the interests of progress.