The 5-147384-4: Three mated stacking heights are available — 6.35mm, 8.13mm, and 9.91mm — all achieved with the same receptacle body by selecting the matching pin header length. This gives the mechanical designer a z-height budget window without requalifying the receptacle.
The harness designer should match it with 28-30 AWG wire in a cable assembly; the current ceiling is set by the contact beam cross-section and the 1.27mm pitch, not by the gold plating. In a quarterly cycling scenario, the contact interface outlasts the product lifetime without fretting corrosion. The solder-tail finish is 150.0 µinch tin — adequate for a reliable solder joint to the PCB pad, though the tin surface is not rated for repeated unmating after soldering.
The 40-position, 2-row layout is fully loaded — all 40 positions are active. The base product number 147384 identifies the family; the -4 suffix specifies the 40-position variant with gold mating and SMT termination.