Unshrouded headers leave the pins exposed after mating — there is no plastic wall around the contact area.
Current, Temperature, and Plating
The mating finish is gold at 3.94 µinch (0.100 µm) — this is a flash plating suited for moderate mating cycles (typically 50–100 cycles) in clean, dry environments. If the application sees frequent reconnects or lives in a corrosive atmosphere, a thicker gold option like the 8.00 µinch on sibling 1376779-2 would extend contact life. The post finish is tin at 78.7 µinch, which solders well into through-hole boards. The thermoplastic insulation material holds the pins in a 2.00 mm grid and keeps the assembly rigid during soldering.
The key difference is the mating gold thickness: 3.94 µinch on this part versus 8.00 µinch on the sibling. That thicker plating buys roughly double the mating cycle life. The sibling also ships in a box rather than a tube. Current rating on the sibling is 3 A versus 2 A here — a marginal gain that may matter if the per-contact load is tight.