Batteries are not replaceable and last up to 2 years. Place the PiepEi in the water at the same time as the other eggs. It doesn't matter whether the water is still cold, warm, or already boiling. The golden PiepEi detects when the temperature reaches 62 degrees and measures when the yolk begins to curdle and harden. This is done through a differential equation.

The golden PiepEi features 3 melodies for 3 levels of doneness:
1. If you want the egg to be soft-boiled, it plays "Killing Me Softly."
2. For medium-soft eggs, you'll hear "I Wish I Were a Chicken."
3. If you want the egg hard-boiled, wait until you hear the "Triumphal March."

This way, water and electricity can be saved since all eggs can be cooked simultaneously. This is especially convenient when there are different preferences for egg doneness.

The PiepEi is definitely worth it. Not only is it practical, but it also serves as a lovely decoration for the kitchen and makes a great small gift.