The 3-178139-2 is a 6-position, 2-row right-angle through-hole header from TE's Dynamic D-3200 series. It mates with the matching Dynamic D-3200 receptacle to form a board-to-board or cable-to-board interconnect rated for 600 V.
Pitch, positions, and plating that drive the fit
At 5.08 mm pitch, the per-contact current ceiling is set by the contact geometry and the 15 µinch gold-over-nickel mating finish. The 6 positions, all loaded, with 2 rows at 0.300" (7.62 mm) row spacing, define the mating half search: any Dynamic D-3200 receptacle with 6 circuits and the same row pitch will fit.