Each unit is made from laboratory grade borosilicate - the same kind of glass used for chemical apparatus throughout the world. It is a very strong material, heat and chemically resistant. Under normal circumstances it will never crack, fade, discolor, haze, or turn opaque. If the part is dropped from a height and it impacts a hard surface it is possible to shatter a part. Spare parts are available in the unlikely event you should need one we also sell spare parts.