Some radiation devices are used to sterilize consumer products. The devices used to do this are called irradiators and generally contain a gamma-emitting sealed source or sources. These devices emit very high amounts of radiation and require significant shielding. Commonly sterilized items include supplies used in hospitals and some food, which is discussed in the Food Irradiation section. Another item being sterilized is mail that is going to certain addresses. With the potential for biological compounds being used as terrorist devices and sent in the mail, irradiation of the mail will sterilize those compounds, rendering them ineffective.