The Yamaha Silent Brass System allows you to practice and play in difficult places until now. You dont have to worry about the time because the sound leaks. Just plug in your stereo earphones anytime, anywhere and instantly create your own studio. Digitally processed rich sound field for playing. Furthermore, using the input and output terminals, you can connect a CD player to play with your favorite artist, or connect an amplifier or tape recorder to ensemble with other instruments.