Lithium batteries are used as backup power sources for electronic equipment. Lithium batteries can be divided into two large groups: those providing full backup power to run a piece of equipment during a power outage; and lithium batteries for memory backup, which does not provide active power to run a piece of equipment. A lithium battery can also be used as a long-term power sources for memory components to retain necessary information. In the United States, lithium batteries carry designations such as AAAA, AAA, N, 1/3 AA, 2/3 AA, AA, 1/2 A, 2/3 A, A, 4/5 Cs, Cs, C, 1/2 D, D. Nonstandard disposable primary battery include prismatic cells, coin or button cells, sachet cells, lantern batteries, and battery packs.