The 77313-424-64LF: 64 positions loaded all the way; the unshrouded header lets you break away sections if the BOM calls for fewer circuits, though the 64-position body stays as one piece.
Current and Contact Reality
Tin is a workable choice for moderate mating cycles (under 50) and non-corrosive environments; the per-contact current stays within the temperature rise limit of the UL94 V-0 thermoplastic housing. Phosphor bronze contact material gives good spring retention and solderability — the 0.266" (6.75 mm) mating length engages fully with standard IDC or crimp receptacles.
The 0.114" (2.90 mm) solder post length suits through-hole boards up to 1/16" thick. Through-hole solder termination — no press-fit or surface-mount reflow. The 0.480" (12.19 mm) overall contact length means the post protrudes enough for wave solder but keeps the profile low on the back side.