PRO-Tector Flash™: the best of both worlds
PRO-Tector Flash™ is a software development kit enabling developers to buy a USB flash drive from any supplier and turn it into a dongle-like device by creating and storing the digital license for a particular software application on it. This approach combines the strong protection of a physical device with the flexibility of a software license.
Roll your own protection
Although Nalpeiron will happily provide blank USB flash drives, developers no longer need to rely on a single company as they do when purchasing dongle hardware.
Instead, they can roll their own protection, purchasing a USB drive with the capacity that they need (up to a maximum of 2GB). PRO-Tector Flash™ puts developers back in control of their own copy protection, making it possible to customise it to suit their customers’ needs.
Users who travel frequently and need to move their license from one computer to another on a regular basis will find the copy protection offered by PRO-Tector Flash™ to be more convenient than dongle solutions. PRO-Tector Flash does not restrict the use of the USB flash drive as a storage device and also provides users with the option to transfer the license from the USB drive to their PC, minimizing inconvenience in the event of a lost flash drive.

For more useful information, See "Combining hardware and software to solve the dongle problem"