The DF59-4S-2V(51): It uses a 0.079" (2.00mm) pitch and mounts via surface-mount technology, with the right-angle orientation keeping the mated connector parallel to the PCB edge. The housing is natural Liquid Crystal Polymer (LCP) with a phosphor bronze contact spring, gold-plated on the mating surface.
Solder retention keeps the part planted during reflow
This receptacle includes a solder retention feature — metal tabs on the body that reflow into the board pads, holding the connector in place against the shear force of a cable mate or vibration. For a right-angle SMT part, that retention is the difference between a reliable solder joint and a lifted pad on the first cable tug.
The 4-position count matches a 4-circuit BOM line. The 0.079" (2.00mm) pitch is tighter than a 0.100" header — the footprint is small enough for dense boards but still hand-solderable with a fine tip. Against the 2-position DF59-2S-2V(51) at the same pitch, the decision is purely circuit count: the 4-position version adds two contacts in the same row length increment.