All electronic equipment needs power. In most cases, this means plugging the equipment into the AC mains. However, power quality can have adverse effects on many components, especially sensitive digital eletronics: Large variations in mains power (brown-outs, spikes and surges) can irreversibly damage equipment; noisy mains (in the electrical sense) and earth loops can seriously effect sound quality. Given the investment that home theatre and audio can represent, some form of power protection and filtration is essential to let the connected equipment shine, while it is kept safe.