The M39012/25-3026 is a protective dust cap specifically designed for SMA jack connectors. It features a 1/4-36 UNS-2A thread for secure attachment to unused ports. The body and rivet are constructed from stainless steel (Alloy UNS S30300, Type 1) and are passivated per AMS-2700 for enhanced corrosion resistance. An attached stainless steel bead chain, approximately 3.25 inches long, prevents the cap from being lost. This component is essential for protecting sensitive RF interfaces from dust, moisture, and other environmental contaminants, ensuring the reliability and performance of the equipment.