Shadow 4 enable continuous, real-time backups of photos, music, videos, and documents to virtual any attached storage device with a drive letter.

What's new & unique:
Supports both one-way backup and two-way synchronization.
Ninja public and encrypted private partition on the same USB drive. (Windows only)
Continuous data protection and schedule backups
Destination Capacity Alert to warn you when your destination is becoming full.
Versioning to allow multiple backup versions of your files.
Drag and Drop plus 1-Click "Quick Restore"
Improved user interface for even easier backup and file sharing
Graph layout of Source and Destination devices toquickly undestand capacity