What This 12-Circuit HPI Receptacle Housing Does
The 0.049" (1.25mm) pitch is the dimension that decides the board layout — every contact centreline is 1.25 mm apart, so the PCB footprint and the mating header must match this spacing exactly. The 12 positions are what the BOM line calls for; confirm your circuit count against this number before committing. In a harness subject to vibration — such as an engine compartment or an industrial cabinet with fans — the latch keeps the mated pair from walking apart.