It uses a locking ramp fastening system to hold the mating pair engaged, and the 0.264" (6.71mm) pitch — matched between rows as well — gives generous creepage for moderate-voltage circuits. You'll need the matching male or female crimp terminals from the 3191 terminal family to populate it. The plug accepts both male and female contact types, so it can serve as either half of a mated pair depending on which terminal you load.
The 0.264" (6.71mm) pitch is the same between rows, giving a symmetrical 2-row grid. That spacing is common across the 3191 series, so the plug mates with any 3191-series header or receptacle that matches the 6-position count and row configuration. The pitch is wide enough to route moderate-gauge wire without crowding the cavity walls.
Panel mount is the intended installation — the plug body has integral mounting ears or features for through-panel fixing.