The 4.20mm pitch and locking ramp fastening make it a standard fit for moderate-current power interconnects where the housing stays mated under vibration.
The crimp termination requires a separate terminal and a hand or auto-crimp tool; the housing itself is just the insulator and locking ramp. For a complete mated pair, you also need the corresponding VAL-U-LOK receptacle housing and female socket terminals.
Locking Ramp Keeps the Mate Secure on a Moving Line
On a harness that sees machine movement or vehicle shake, that ramp is what keeps the connection from backing off a half-turn. No secondary lock or screw is needed for the housing mate itself, though the terminal position assurance comes from the crimp quality and full seating of the pin into the cavity.