The Amphenol 431-10000 is a protective dust cap (cover) for the 4.3/10 connector interface, designed to seal an unmated plug or receptacle. The nickel-plated brass body resists corrosion in outdoor or washdown environments, and the attached chain keeps the cap tethered to the cable or panel so it doesn't walk off between connections.
Construction and Sealing
Body is machined brass with a nickel finish — standard for RF connector caps that need to survive repeated mating and exposure to weather. The chain is a captive feature, so the cap stays with the cable assembly and can't be misplaced during field service.