The Silent Brass System consists of the ST9 module and mute.

The new improved ST9 personal studio has been reduced in size and weight, approximately 1/4th that of the previous model. It has a tiny amplifier which offers choice of clean sound or reverb/echo enhanced sound. Its lets you hear your owm playing at the volume you are accustomed to while others hear only the practice mute. The Aux IN is direct line-in for playing with CD's or other recordings.