There are many styles of mandolin, but the three most common types are the "Neapolitan" or "round-backed" mandolin, the "archtop" mandolin and the "flat-backed" mandolin. The round-backed version has a deep bottom, constructed of strips of wood, glued together into a bowl. The archtop, also known as the "carved-top" mandolin has an arched top and a shallower, arched back both carved out of wood. The flat-backed mandolin uses thin sheets of wood for the body, braced on the inside for strength in a similar manner to a guitar. Each style of instrument has its own sound quality and is associated with particular forms of music. Neapolitan mandolins feature prominently in European classical music and traditional music. Archtop instruments are common in American folk music and bluegrass music. Flat-backed instruments are commonly used in Irish, British, and Brazilian folk music.