DF40C-44DP-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board connector designed for compact electronic assemblies that need reliable high-density interconnection. As part of the DF40 family, this 44-position, 0.40 mm pitch plug connector is well suited for portable devices, industrial control modules, embedded systems, communication equipment, and other space-constrained PCB designs where low profile and stable SMT assembly are important. Features such as gold contact finish and solder retention support dependable mating performance and manufacturing robustness. The part is listed as Active, with market popularity noted as high and supply-demand currently balanced, making it a practical option for ongoing designs and production builds. Lifecycle data in the input shows an estimated EOL date of 2027, so engineers planning long service programs should consider monitoring future notices and qualifying alternates early. RoHS compliance information is not explicitly provided in the supplied specifications, so compliance status should be treated as information not available pending confirmation from Hirose documentation or authorized sourcing channels.