DF40B-10DS-0.4V(58) from Hirose Electric Co Ltd is a fine-pitch board-to-board mezzanine receptacle designed for compact electronic assemblies where space, profile, and interconnect reliability are critical. As part of the Rectangular - Board to Board Connectors - Arrays, Edge Type, Mezzanine category, it is well suited for portable devices, embedded control boards, industrial modules, medical electronics, and other high-density PCB stacking designs. The 0.40 mm pitch, 2-row layout, surface-mount format, and solder retention feature support dense placement and secure assembly in automated production environments. With supply listed as shortage, this part may require proactive sourcing and buffer planning for ongoing builds or new designs. Lifecycle status is currently information not available, so engineers should confirm long-term availability directly with Hirose or the latest authorized channel data before release to production. RoHS compliance information is also not explicitly provided in the supplied specifications; compliance should be verified using the official datasheet, manufacturer declaration, or distributor documentation.