Not all rhythm sections follow the standard model of drummer-bassist-chordal instrument. Some bands have no drummer. In bands without a drummer, one or more instruments from the rhythm section often play in styles that replace the drum kit role—that is laying down the beat and backbeat. Traditional bluegrass bands typically do not have a drummer. In bluegrass bands, the timekeeping role is shared between several instruments: the upright bass generally plays the on-beats while the mandolin plays chop chords on the off-beats, with the banjo also keeping a steady eighth note rhythm.