DF40HC(3.0)-44DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board receptacle designed for compact electronic assemblies where space, profile, and interconnect reliability matter. With 44 positions, 0.40 mm pitch, dual-row SMT mounting, and a 3 mm mated stacking height, it fits high-density portable, industrial, medical, and embedded designs that require stable board interconnection in constrained layouts. Engineers typically select this Hirose connector family for compact control boards, display modules, handheld devices, and communication equipment that benefit from precise alignment and gold-finished contacts. Based on the provided data, the part status is Active, which is favorable for ongoing procurement and new design consideration, although lifecycle should still be confirmed through the manufacturer for long-term programs. RoHS compliance information is not explicitly provided in the supplied specifications, so compliance status should be treated as information not available until verified through official Hirose documentation or authorized distributor compliance records.