Our stainless steel food warmer is made from very high quality stainless steel cover and borosilicate glass and metal rack, but for glass bowl, yet fragile glass - always be careful not to crack it when cleaning, handling or using it. Safety notice: The metal rack and lid could not be put into microwave , but the glass bowl can use Oven and Microwave Safe, Glass heat resistan-40℃ to 300℃, Refrigerator and freezer safe,The use of sharp metal tools (e.g. knives, forks) may damage (scratch) the surface. The use of intense cleaning material can damage the surface. Negligent handling (e.g. of the lid) may lead also to surface damage.