Nickel Metal Hydride chemistry was one of the most widely used battery technology until the introduction of Lithium-Ion batteries. Ni-MH batteries are still used in a variety of applications today, in the form of rechargeable AA, AAA, C, D and 9 volt consumer battery sizes, in the form of OEM batteries for cordless Phones, two-way radios, power tools and more. Ni-MH batteries are still considered to be the most cost effective power solution for electronic devices and they boast a shelf life of 10 years, the longest among modern rechargeable batteries.