The D-Rive is the primary digivice used by the tamers of Digimon re:CONNECT.
The D-Rive first and foremost serves as a sort of battery, absorbing and storing power and data from digimon that have been defeated, and reconfiguring it for use by its corresponding digimon. The D-Rive is able to absorb data much more efficiently than a digimon's natural processes, especially when the resultant data cloud is thinned by the effects of the real world. It does, however, require user input to be used to its fullest potential; as such, a D-Rive is usually most useful in the hands of an outside party (read: a human). It seems to foster a resonant connection between its users with use over time, but the exact mechanics and ramifications of this are unknown; while it may simply be that the users grow closer as they fight and work in tandem, the connection seems stronger.
(It's pronounced as "derive", by the way.)
The D-Rive primarily exists to serve its purpose as a 'backup battery', and its other functions are rudimentary, but useful nonetheless. Such features include a clock (accurate within a millionth of a second), a charge meter displaying current reserve data levels, a basic radar for detecting surges of digital energy (read: Digimon) in the real world, and a USB-compatible port. When connected to a computer via this port, the D-Rive produces a cryptic, unreadable encrypted file.