Ballast set for the MP20S49 medium-pressure UV lamp used in ATG/Willand UV disinfection systems (the range now carried as Evoqua ATG UV). Norwegian forkobling denotes the lamp's control gear; the item is supplied as a set rather than as a single component. Ordered when the control gear, not the lamp itself, has failed. OEM listing title: Forkobling uv-lamp MP20S49 -SET.