Boss is a manufacturer of effects pedals for electric guitar and bass guitar. It is a division of the Roland Corporation, a Japanese manufacturer that specializes in musical equipment and accessories. For many years Boss manufactured a range of products related to effects processing for guitars, including “compact” and “twin” effects pedals, multi-effect pedals, electronic tuners and pedal boards. In more recent times, Boss expanded their products line to include Digital Studios, rhythm machines and other electronic equipment.

Source: http://en.wikipedia.org