Dust caps for the plug and the socket (cable or panel) variations that maintain IP65 rating when fitted.
Binder M9 Subminiature Connectors, Metal, IP67 - Series 712
Subminiature circular connectors that provide IP65 protection and mate by screw locking. Cable termination is by solder bucket. The metal front end construction makes sure there is a rugged performance whilst the rear end plastic construction incorporates cable clamping for cables up to a 5mm diameter (maximum). Assembly instructions are supplied.