DF37B-24DP-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board connector designed for compact electronic assemblies that need reliable mezzanine interconnection in limited space. As part of the DF37 series, this 24-position, 0.40 mm pitch header is well suited for portable devices, industrial control modules, embedded computing boards, medical electronics, and other dense PCB layouts where low profile stacking is important. Engineers typically select this type of connector for its space-saving form factor, gold-finished contacts, surface-mount compatibility, and solder retention feature that supports assembly stability. The listed product status is Active, which is a positive signal for ongoing design consideration, although teams should still confirm long-term availability directly with the manufacturer or authorized channel before locking a production BOM. RoHS compliance information is not explicitly provided in the supplied specifications, so the compliance status should be treated as information not available pending confirmation from official Hirose documentation or supplier compliance records.