Covers are provided with a thermometer for the temperature checking. The pots are used for reductiv cooking without water or fat addition, or for pressure cooking with the special new lid. The cooking units are not simple pots, but a real reductiv-cooking-system, where each pot may be combined on another at one's will (perfect fitting of the items to one-another). The higher thickness of materials and the greatest accuracy in the execution, make the superior quality of the products.