leather. It is held under one elbow and squeezed to provide a continuous stream of air to the chanter, even though the air goes into the bag unevenly.

There are two main ways of inflating the bag. In mouth-blown instruments, the player blows into the bag through a blowpipe. In bellows-blown instruments, the players has a bellows strapped to his or her other arm, which feeds air into the bag. Mouth-blown instruments are simpler and more common than bellows-blown ones. The bellows has the advantage that the air passing through the reed is dry, so the behaviour of the reed is much more consistent than in a mouth-blown instrument. A typical reed in a bellows-blown bagpipe may last years or even decades. Compare this with an oboe reed which is held in the player's mouth - it generally lasts a few weeks at most. The reed in a mouth-blown bagpipe is somewhere in between.

Most bagpipes have an additional feature: drones. These are extra pipes which play a continuous unchanging note. Simple bagpipes of Eastern Europe may have just a single drone. More advanced bagpipes may have two or three. The most elaborate have four.