This is a 20ml bottle of Choroi's Flute Oil for our Pentatonic flutes. To maintain your flute, oil it regularly (at least once a month), both inside and out, and wipe inside with the swab after each use. To oil inside the pipe, place some drops of oil on the swabbing paper at the tip of the swab. In addition, place a drop of oil in the slit where you blow, whenever the wood in this area appears lighter in color. Made from Linseed Oil.