The 103638-3: The keying slot prevents mis-mating, and the 4-wall shrouding protects the pins during handling and mating. This connector is intended for board-to-board or cable applications in automotive, general purpose, medical, and telecommunications equipment.
This gold plating provides corrosion resistance and maintains low contact resistance over repeated mating cycles, making the header suitable for applications where the connector may be disconnected and reconnected in the field. This is a traditional solderable finish, but note the part is RoHS non-compliant due to the lead content.