With the Egg Timer you'll cook the perfect hard-boiled egg every single time! Using the Egg Timer is simple, just throw it in with your eggs and keep an eye on the color. As the egg cooks the timer gets darker in the middle. As this darker region expands it will come in contact with one of three lines (hard, medium or soft) that correspond with your tastes. The sensor even accounts for the number of eggs, the amount of water, and the altitude the eggs are being cooked at. In other words, as long as you are paying attention, you can't really mess this up.