DF40C-30DP-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board connector designed for compact electronic assemblies where density, low profile, and reliable mating performance are important. As a 30-position, 0.40 mm pitch plug with SMT mounting and gold contact finish, it fits space-constrained products such as portable devices, industrial control modules, embedded systems, and communications hardware. Engineers typically select this series for stacked PCB designs that need controlled mating height options and dependable solder retention during assembly. Based on the provided status, this part is Active, which supports ongoing design consideration, although long-term planners should still monitor manufacturer updates and supply conditions. RoHS compliance information is not explicitly provided in the supplied specifications, so compliance should be treated as information not available until confirmed through the official datasheet, manufacturer declaration, or authorized distributor documentation. For procurement teams, current supply is listed as sufficient, making it a practical option for both production and maintenance sourcing.