The La Clef du Vin Travel from Peugeot of France is a patented metal alloy that will reveal a wine's aging potential. The wine tester works on all types of wine, whether it be red, rose, sparking, white, or even sweet wine. Every second you put the alloy disk on (at one end of the Clef du Vin) into the wine will mimic one year's aging. This effect is cumulative and irreversible. The La Clef du Vin is ideal for wine connoisseurs, is made in France, comes in a gift box, and has a 2 year warranty.