Rubber shell connectors also called Packard connectors. Connectors are part number MS27143-1 (female electrical connector/male rubber shell). Made in USA. Ozone resistant rubber.
Connector assembly sold individually, price is for one each of: rubber shell, washer, and terminal socket.
Terminal ends can be soldered or crimped on to the wire. These are made for 12 AWG stranded copper wire. Connectors are used on many Military vehicles but are good for custom projects too.
Note- this 12 AWG connector is often used on vehicle's main power feed to control panels, circuit breakers, and switches.