DF40GB(1.5)-10DS-0.4V(51) from Hirose Electric Co Ltd is a fine-pitch board-to-board mezzanine receptacle designed for compact electronic assemblies where space, alignment reliability, and signal integrity matter. With a 0.40 mm pitch, 10 positions, dual-row layout, gold-plated contacts, and shielded construction, it is well suited for densely packaged consumer devices, portable instruments, industrial control modules, and embedded boards that require low-profile stacking. Surface-mount termination and tape-and-reel packaging also support automated high-volume assembly. Features such as solder retention and a 1.5 mm mated stacking height make it attractive for slim PCB interconnect designs. Based on the provided data, lifecycle status is unknown, although supply and demand is listed as normal, so designers should verify long-term availability directly with Hirose or an authorized source before locking it into new programs. RoHS compliance information is not available in the provided specifications; engineers should confirm current RoHS and related material declarations through the official manufacturer documentation.