The Hirose HRM-514(40) is an SMA dust cap (cover) designed to protect unmated SMA jacks from debris, moisture, and mechanical damage when the interface is not connected. It is part of the HRM series of SMA accessories. The cap carries a gold body finish and a gold center contact finish, matching the plating typical of precision SMA interfaces to avoid galvanic corrosion. A built-in chain is attached to the cap so it stays tethered to the cable or panel — a detail that matters in field-service or test-bench setups where a loose cap is the first thing lost.
What the gold finish and chain mean for the fit
The gold-over-nickel body and center contact finish on the HRM-514(40) is the same plating grade used on the mating SMA jack's interface. That match prevents the dissimilar-metal corrosion that can occur when a nickel or tin-plated cap is left on a gold-plated jack in a humid or outdoor environment. The chain is listed as a feature — it keeps the cap captive at the connector location, which is useful for test equipment, antenna ports, or any SMA jack that gets cycled between capped and mated states regularly. The cap is packaged in a bag.