RS PRO Circular Connector, 3 Contacts, Cable Mount, Plug, Male, IP68

From RS Pro, these threaded plugs & sockets are serious contenders for your application. This particular model has a bigger and stronger shell complimented by its cable to cable (inline) connection. That coupled with the IP68 rating, makes sure that this industrial connector excels in harsh environments. Typical applications include outdoor security, medical devices, communications and marine equipment. When choosing a inline connector, this version should really be one you consider.

Threaded Coupling