DF40GB(3.0)-70DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch board-to-board mezzanine receptacle designed for compact electronic assemblies where space, stacking height, and signal integrity matter. With a 0.40 mm pitch, 70 positions, dual-row layout, and 3 mm mated stacking height, it fits portable devices, industrial control modules, communication equipment, embedded systems, and other dense PCB interconnect designs. Features such as gold contact finish, shielding, and solder retention support reliable mating and stable assembly in surface-mount production environments. Within the connectors and interconnects category, this part is positioned for engineers who need a low-profile, high-density interconnect between stacked boards. Lifecycle status is currently listed as unknown, so design teams should confirm current manufacturer support before locking it into long-term programs. RoHS compliance information is not available in the provided data; engineers should verify RoHS and related material declarations directly with Hirose documentation or authorized supply channels before compliance-critical deployment.