6.35 mm pitch, 3-position single-row header
The 643413-1: The 0.250" (6.35 mm) pitch sets the board footprint for this through-hole header — wide enough to route a power or signal trace between pads without necking down. That latch keeps the pair together under vibration, which matters in industrial panels or equipment that sees transport shock.
Tin-plated contacts and UL94 V-2 housing
Tin-on-tin mating interface (contact finish on both sides is tin) is cost-effective for moderate mating-cycle duty — think a few hundred cycles over the product life. The natural colour helps visual inspection of the latch engagement on the line.