The 0.024" (0.60mm) pitch packs 120 circuits into a dense two-row layout, which means the board-side footprint is tight — routing a full 120 signals through a 0.60mm pitch requires careful trace-width planning and at least a four-layer PCB to escape the inner rows. The header uses outer shroud contacts, so the mating receptacle surrounds the header body, giving the pair a self-aligning engagement.
The FX8C-120P-SV6(91) has a height above board of 0.427" (10.85mm) and supports mated stacking heights of 11mm and 16mm. The 11mm stack is achieved when mated with the standard FX8C receptacle; the 16mm stack uses a taller receptacle variant. This is the dimension that decides whether the connector fits the z-height budget between two parallel PCBs — a common constraint in ATCA blades, server line cards, or any mid-plane architecture where the mezzanine card sits above the backplane. The 10.85mm header height is the taller option in the FX8C family; if your enclosure has less than 11mm of clearance between boards, you need the lower-profile sibling.