The 68021-170HLF: All positions are loaded, meaning every pin is present and the footprint is a full 2×35 array. The pins sit parallel to the board surface, so the header routes the signal along the board edge and keeps the z-height under 0.190" above the PCB.
In a 70-position header, the total current across all pins is 210 A, but the per-contact ceiling stays at 3 A. For a board-to-board interconnect that gets disconnected during field service, this plating grade avoids contact fretting over years of quarterly reconnects.
RoHS compliant per the manufacturer's standard declaration. The insulation is black UL94 V-0 rated thermoplastic.