The 770078-1: The 0.198" (5.03mm) pitch gives enough spacing for 14-18 AWG power circuits without crowding the crimp terminals. The natural nylon (PA) housing carries a detent lock that snaps onto the mating receptacle — positive retention in moderate vibration without a secondary latch.
If you need more circuits, the 1-1644055-3 is a 6-position dual-row plug with a 6.35mm pitch and a latch holder instead of the detent lock. The 5.03mm pitch here is tighter than the 6.35mm of that sibling, which saves board or harness real estate when 4 circuits are enough.
Crimp termination — you select the male or female pin (sold separately) and crimp it onto the wire, then insert it into the housing. The detent lock engages with the mating receptacle housing from the same series.