Coupling piece that joins the wiper rod to the operating lever in ProMinent ultraviolet reactors, original part number 1027930. It transmits the lever motion to the wiper mechanism that cleans the outside of the quartz sleeve, so a worn or damaged coupling shows as an incomplete sweep and falling measured intensity even with good lamps and a good wiper. Replace it whenever the wiper assembly is disturbed if the seat is scored or has play. ProMinent part reference 1729-0712.