With airlines continually adding extra baggage costs and overweight fees, it can be tricky to know exactly how much extra you might pay .
Marcella Maltese and Lin Wei have devised a simple solution to this dilemma with their Gravity Ruler. The tiny, bungee cord based device gives travelers a quick estimation of what their bag weighs.
The two design students had great success selling prototypes at the Travel Trading Fair in Milan, and are currently looking for a manufacturer.
[via Slash Gear]