Wiper teardrop for Hanovia medium-pressure ultraviolet disinfection systems, part 320305-04. The teardrop is the tapered wiper body that rides the quartz sleeve — its profile is what gives the wiping edge an even contact pressure along the sleeve rather than a single hard line. The quartz sleeve is the only optical path between the lamp and the water, so any film of scale or iron on its outer surface cuts the delivered UV dose. The wiper sweeps the sleeve on a timed cycle to keep transmission at the design figure. It is a wear part and is replaced at service alongside the wiper ring. Reference number 22126-0916.