Some pan flutes are tunable, while others are non-tunable. Tunable varieties include corks inside all tubes, which consist of saliva-resistant synthetic rubber components. These pieces can be pushed to modify tunings. As a result, they can match all songs the musician likes to play. Sometimes they get out of tune, but you can fix them within no time. Tubes of non-tunable flutes are fixed in particular tunings. They barely get out of tone but once they do, tuning back will not be easy.