The WJ-HDE510B is a DVD Extension Unit for connection with the WJ-HD500
Digital Disk Recorder for copying or backing up recorded data. The system
can be extended by connecting up to 6 extension units in an SCSI chain while
the DVD extension unit containing up to two HDDs.
The DVD-RAM stands for digital versatile disk-random access memory.
The DVD-RAM can be stored high capacity data for making a backup.