The Amphenol 79425-156HLF is a 56-position, dual-row unshrouded header in the BERGSTIK® II series, on the standard 0.100" (2.54 mm) pitch that matches legacy through-hole board layouts.
The 56 positions of the 79425-156HLF are loaded fully across two rows at a 0.100" row spacing. The decision between this and a lower-position variant is a straight circuit-count match to the BOM.
The 0.190" (4.83 mm) mating pin length gives a solid wipe depth in the matching receptacle, and the 0.120" (3.05 mm) solder post length suits standard 0.062" PCBs. The phosphor bronze contact material is a standard spring alloy for this class of header.