Heat insulation balls with bag, perfect for adapting to all container sizes. Up to 90% reduction in evaporation, water, and heat loss when cooking with a thermal flask. Reduced energy loss during sous vide cooking due to surface charge between water and air. Increased temperature accuracy of your Roner immersion circulator. Reduced risk of burning due to floating insulating balls. The hollow, insulated spheres allow you to cook for hours without adding water.