The 9-146252-0-22: The square male pins are gold-plated on the mating surface (15 µinch) and tin-plated on the solder posts, giving you a corrosion-resistant contact interface for repeated mating cycles while keeping the solder-joint cost reasonable.
The 3 A rating is typical for signal-level circuits in this pitch class; if your design needs higher current per pin, you'd look at a wider-pitch or heavier-contact series.
