Flashbag USB Drive Visually tells you how full your disk is... amazing!

Flashbag USB Drive: "The Russian-designed Flashbag USB drive offers an unorthodox method of knowing how much free space you have left. A built-in micro pump will inflate the device as the USB drive begins to fill up. When full, an error message 'There is not enough free space.' will be displayed, and the Flashbag will be bloated at its maximum capacity. Even when unplugged, the Flashbag will not deflate, so you will always have a visual reminder of how much space there is left. The only grouse would be USB ports that are situated too close to each other. You definitely can't fit the Flashbag between two other USB connections when full."

-e