DF40C-30DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch rectangular board-to-board receptacle designed for compact electronic assemblies where space, profile, and interconnect reliability are critical. With a 0.40 mm pitch, 30 positions, dual-row layout, and 1.5 mm mated stacking height, it is well suited for mobile devices, wearable products, industrial control modules, compact medical electronics, and other dense PCB designs requiring low-profile mezzanine connections. Its gold contact finish supports stable signal performance in repeated mating environments, while SMT mounting and tape-and-reel packaging align with automated high-volume production. The supplied product status is Active, which supports ongoing design consideration, although the lifecycle field is listed as unknown and should still be verified through the latest manufacturer documentation. RoHS compliance information is not explicitly provided in the input data, so engineers and procurement teams should confirm current RoHS and any related environmental declarations directly with Hirose or authorized distribution sources before release to production.