The AAA battery (also called R03 or "triple-A"), is the smaller
sister (or brother if you prefer your batteries to be male) of the AA battery.
It is gaining in popularity quickly, and is already the second most common
battery sold in the UK.
All AAA batteries share the same cylindrical shape with a height of 1.752" (44.5mm) and a diameter of 0.413" (10.5mm). Most AAA batteries use alkaline technology, with a voltage of 1.5V. The AAA battery is however also available as a rechargeable battery. The NiMH AAA rechargeable battery is rated at 1.2V, but performs as well as the alkaline version in modern high-drain applications, such as digital cameras.