Wedeco reactors with a wiper sweep the outside of the quartz sleeve to remove the scale and film that attenuate UV-C before it reaches the water. A wiper that is worn or wiping unevenly shows as falling measured intensity on lamps that are themselves still good. This is the wiper ring for the KM1000. The matching O-ring is stocked under item 13124-0909. Wedeco was founded in Herford, Germany in 1976 and is now a Xylem brand.