Pads are inserted into the underside of a flutes keys in order to seal the tone-hole when the key is depressed. Flute pads are made from woollen felt wrapped around a cardboard backing to give them the required rigidity. The pad is then covered with pad skin, which is actually a product obtained from bovine stomach lining, thereby giving it the smooth and air-tight finish thats necessary for it to effectively seal the tone-hole. Pads must be perfectly even and flat and precisely in line with their corresponding tone-holes in order for the instrument to sound properly.
