Pitch, positions, and what mates with it
The 643495-2 is a 5-position header from the MTA-156 series, with a 0.156" (3.96mm) pitch that sets the board footprint and matches the MTA-156 receptacle family. Only 3 of the 5 positions are loaded with pins, so the BOM line for the mating half should account for the actual circuit count, not the housing size. The shrouded-1 wall and friction lock give this header a positive retention against vibration — a step up from unshrouded breakaway headers — without needing a secondary latch. It mates with standard MTA-156 crimp-socket housings (like the 640550 series) using the same 0.156" pitch.
Current rating and temperature ceiling
The tin-plated mating surface and post handle the current the attached wire can carry, up to the 600VAC voltage rating.