DF37C-40DP-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board connector designed for compact electronic assemblies where low profile and dense interconnect routing are critical. With 40 positions, 0.40 mm pitch, SMT mounting, and a 0.98 mm mated stacking height, it is well suited for portable devices, industrial control modules, embedded computing boards, medical electronics, and other space-constrained designs that require reliable mezzanine connections. Engineers typically select this series for its compact form factor, gold contact finish, and suitability for automated reel-based assembly. Based on the provided specification, the manufacturer status is Active, which supports use in ongoing production, although the supplied lifecycle field is listed as unknown and should still be confirmed through official manufacturer documentation. RoHS compliance information is not explicitly provided in the input data, so compliance status should be treated as information not available pending datasheet, declaration, or manufacturer confirmation before release to regulated markets.