Amphenol Socapex, 2M801 4 Way Flange Mount MIL Spec Circular Connector Receptacle, Socket Contacts,Shell Size 9,

The Amphenol Socapex 2M series micro-miniature dual-start ACME thread coupling connector are a small, lightweight option for mil-spec performance that can withstand harsh environments. They are quick-mating and a variety of styles and options are available. The inserts of this connectors is made from polyphenylene sulphide and the shell is olive drab cadmium plated.

Most durable
Integrated backshell
Gold plated copper alloy contact
Aluminium alloy shell