Redi-Temp^™ is a valve placed on the cover. It takes the guesswork out of cooking when the cooking temperature inside the cookware reaches 82°C. That is when the Redi-Temp^™ valve will sound much like a teakettle. You can be in the other room and you will know when the proper cooking temperature is achieved. When the whistle is heard, it means it is time to turn the burner to the off position and close the Redi-Temp^™ valve. The construction of Royal Prestige^® and the vapour seal covers retain the heat so well, that the foods will finish cooking with the heat they retain. This way you can minimise energy consumption by using medium for a few minutes and then turning the burner off, versus keeping it on a medium-high to high setting throughout the entire cooking process.