The FCI 79821-128HLF is a 28-position, dual-row unshrouded header from the BERGSTIK® II series, designed for board-to-board stacking applications where a standard 0.100" (2.54 mm) pitch and through-hole solder termination are specified.
The 0.100" (2.54 mm) pitch is the classic square-pin grid — every board house knows the drill pattern, and the 0.025" square pins drop into standard stamped receptacles. The 0.730" (18.54 mm) overall contact length includes a 0.430" (10.92 mm) mating tail and a 0.200" (5.08 mm) solder post, which sets the board-to-board stack height when mated with a standard receptacle.