DF40GB(3.0)-48DS-0.4V(51) is a Hirose Electric Co Ltd rectangular connector receptacle designed for compact board-to-board interconnect applications where fine pitch density and multi-row signal routing are important. Within portable electronics, embedded control assemblies, display modules, and other space-constrained designs, this style of connector is typically selected to support reliable interconnection in tightly packed layouts. Based on the provided data, it is a 2-row, 0.40 mm pitch receptacle supplied in bulk and noted as requiring a holder for mounting. The supplied specifications also indicate an obsolete part status, which makes it more suitable for sustaining existing designs than for new platform development unless long-term supply is secured. RoHS compliance information is not available in the provided specifications, so engineers and sourcing teams should verify current environmental compliance directly through official Hirose documentation or manufacturer-authorized sources before qualification.