IEC codes for AA batteries include the popular LR6 for AA alkaline batteries and HR6 for NiMH rechargeable batteries. The normal voltage for these batteries is 1.5V, while rechargeable batteries usually provide 1.2V. The new AA lithium batteries provide much higher capacity for a slightly higher price. Introduced in 1907, the AA battery size was standardized by the American National Standards Institute (ANSI) in 1947, but had been used in flashlights and electrical novelties for some time before formal standardization. ANSI and IEC battery nomenclature gives various designations for cells of this size, depending on cell characteristics and chemistry. Each AA battery has a length of 51mm and a diameter of 14mm. The formats in which the AA battery is available are, alkaline batteries, salt batteries, long-lasting and rechargeable lithium batteries of different capacities. AA alkaline batteries have a storage life of around 6 years, while AA lithium equivalents last up to 9 years before use. Rechargeable AA batteries are now available in NiMH with capacities up to 2850mAh and are also available in the new "pre-charged" technology that allows you to use them, directly from the package.