Fermenting crock weight stones are used to keep vegetables submerged in the brine during the fermentation process. They are designed to fit inside fermentation crocks and rest on top of the fermenting food, applying gentle pressure to keep the contents below the brine level. This prevents exposure to air, which can lead to mold growth or spoilage. Their weight and shape create an anaerobic (oxygen-free) environment crucial for successful lacto-fermentation of foods like sauerkraut, kimchi, and pickles. Weights help keep food submerged in the brine while fermenting. Made for the numbered stoneware crocks. USA made in Ohio.