DF37NC-44DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board receptacle designed for compact electronic assemblies where space, low profile, and reliable interconnection matter. As part of the DF37 series, it is well suited for portable devices, industrial modules, embedded control boards, display interfaces, and other high-density PCB stacking applications that benefit from a 0.40 mm pitch and surface-mount implementation. Engineers typically select this connector family when designing thin products that require stable mating alignment and efficient board space usage. The part is supplied in tape-and-reel packaging, which supports automated assembly workflows in volume production. Based on the provided specifications, this connector is RoHS Compliant, making it suitable for designs targeting regulated global markets; however, teams should still confirm the latest material declaration and compliance documents with Hirose. Lifecycle status is currently listed as unknown, so purchasers should verify current production status and stocking conditions before committing it into new or long-life programs.