The Great Highland Bagpipe is famous for its unrelenting, continuous sound. This is achieved through the use of an airtight reservoir, or 'bag,' which the player keeps inflated by blowing into a blowpipe. While the player takes a breath, they squeeze the bag with their arm to maintain a constant flow of air through the 'chanter' (which plays the melody) and the 'drones' (which provide constant background notes). Because the air pressure is constant, the reeds never stop vibrating, meaning the instrument cannot produce silence between notes. To separate notes of the same pitch, bagpipers use 'grace notes'—extremely fast decorative notes that create the illusion of articulation. This unique mechanical requirement led to the development of a highly complex fingering system and a repertoire of music specifically designed for an instrument that literally never stops for a breath.