The 1-103639-5: The 4-wall shrouding and latch holder fastening make it suited for board-to-board or cable connections where vibration resistance matters — automotive, medical, telecom, or general-purpose gear.
Keying slot and latch retention
A keying slot in the housing prevents mis-mating with receptacles that lack the matching key — a simple insurance against reversed or wrong connector insertion. The latch holder locks the header to its mating half; once engaged, it resists unseating from cable tug or vibration better than a friction-only fit.
It is RoHS non-compliant due to tin-lead plating — check your assembly's exemption status if you're shipping to RoHS-regulated markets.