The 3-641209-3: 3.96mm pitch on a single row with 3 positions loaded — the board footprint needs 0.156" between pin centers, leaving room for trace routing between pads on a 2-layer board. The 0.400" mating pin length gives the receptacle a solid wipe before the friction lock engages, and the 0.125" solder tail fits standard 1.6mm boards without bottom-side protrusion issues.
30 µinch gold over copper alloy on the mating face — rated for repeated mating in industrial environments where tin would fret under vibration.
ROHS3 compliant and UL94 V-0 rated housing — meets the flame and material restrictions for equipment inside an enclosure.