The Hirose HR30-6R-C(31) is a black chloroprene rubber cap cover for the HR30 series circular connectors, specifically sized for shell size 6 receptacles. It seals the receptacle face against dust and water ingress when unmated — think of it as the boot that keeps the contacts clean on a panel or cable end that sits disconnected between service intervals. The integrated strap with ring tethers the cap to the cable or panel so it doesn't wander off in a toolbox or get kicked under a machine skid.
Dust-Tight and Waterproof — What That Means in the Field
The cap carries a dust-tight, waterproof seal when installed on the mating receptacle. The chloroprene rubber material holds up to weather, oil, and general industrial grime — it's the same stuff used for gaskets on outdoor junction boxes. Water finds the open splice, and this cover is the cheap insurance that keeps moisture out of an unmated HR30 receptacle on a sensor head or remote I/O box. The strap with ring means you can lash it to the cable jacket or panel bracket so it's always right there when you pull the plug.
Shell Size 6 — Not a Universal Fit
This cap fits HR30 receptacles of shell size 6 only. The HR30 series uses shell sizes to key the cap to the receptacle diameter — a size 7 cap (HR30-7R-C(31)) is physically larger and won't seal on a size 6 receptacle. If you're capping a size 7 receptacle or a size 8 plug, grab the matching shell size cover. No mixing sizes; the seal depends on the interference fit of the rubber over the receptacle rim.