Abstract: A piece of pad for use with a key cup of a woodwind musical instrument. The pad is made of either a silicone rubber only or a felt containing therein a silicone rubber, and has a flat and smooth bottom surface. The pad is fitted in the key cup with the bottom surface thereof facing a tone hole of the instrument. The silicone rubber assures desirable physical properties of the pad such as an appropriate elasticity or flexibility, and the tone hole of the instrument can be positively closed with the flat and smooth bottom surface of the pad upon pushing of the key cup by the instrument player.