DF40HC(2.5)-20DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board mezzanine receptacle designed for compact electronic assemblies where space, stacking height, and signal density matter. As part of the DF40 series, it is well suited for portable devices, industrial control modules, embedded computing platforms, communication hardware, and other PCB designs that require reliable interconnects in a low-profile surface-mount format. Engineers typically choose this connector family for dense layouts, precise mating alignment, and proven Hirose connector performance in high-volume manufacturing environments. Based on the provided specification, the product status is Active, which supports ongoing design consideration, although the broader lifecycle status should still be verified through the manufacturer or authorized sources. RoHS compliance information is not explicitly provided in the input data, so compliance should be treated as information not available until confirmed by the official datasheet, manufacturer declaration, or distributor compliance documentation. For regulated builds, procurement teams should also confirm REACH and material declarations before release to production.