Also called tinwhistles or simply whistles, pennywhistles are cylindrical or conical flageolets (end-blown fipple flutes) with 6 fingerholes, related to recorders but missing the thumbhole and the extra hole for the little finger of the lower hand. Players reach a higher octave by "overblowing." Pennywhistles are very popular for traditional Celtic music. They are made of a variety of materials and in various keys, but are most commonly found in wood or metal versions in the key of D, often with a plastic mouthpiece. Whistles are portable, cheap, readily available, and easy to play!