DF37C-50DP-0.4V(51) from Hirose Electric Co Ltd is a 50-position rectangular board-to-board mezzanine connector designed for compact electronic assemblies that need fine-pitch interconnection and low-profile stacking. As part of the DF37 series, it suits portable devices, industrial control modules, communication hardware, and other space-constrained PCB designs where reliable signal routing between parallel boards is important. Engineers typically choose this type of connector for dense layouts, surface-mount assembly, and consistent mating performance in miniature products. The listed product status is Active, which is a positive indicator for ongoing design use, although lifecycle planning should still be verified 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 confirmed by an official Hirose datasheet, declaration, or distributor documentation. For regulated designs, engineers should also request current material compliance and sourcing confirmation before release to production.