DF37C-44DP-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board connector designed for compact electronic assemblies where space, stacking height, and signal density matter. As part of the DF37 series, it fits applications such as portable devices, industrial control modules, embedded systems, display interfaces, and other high-density PCB interconnect designs that require a low-profile mezzanine connection. Engineers typically choose this type of connector for reliable SMT assembly, compact 0.40 mm pitch routing, and multi-position signal transfer in tightly packed layouts. Based on the available data, the lifecycle status is currently unknown, so design teams should confirm long-term availability with the manufacturer or an authorized source before locking it into new production. RoHS compliance information is not explicitly provided in the supplied specifications, so compliance should be treated as information not available pending official confirmation. For regulated programs, engineers should verify current RoHS and related material declarations directly from Hirose documentation.