Product details:

Practice anywhere, any time Other people hear practically nothing, but you can hear yourself playing at full volume. The SILENT Brass system combines a high-performance practice mute with a built-in microphone that plugs into a receiver unit. With headphones connected, you'll hear yourself playing clearly. The mute offers superior muting performance, excellent intonation over a wide pitch range, and natural playability. Brass Resonance Modeling technology makes the sound you hear through the headphones incredibly realistic, almost as if you didn't have a mute at all. By connecting to a portable audio player or smart phone with audio playback capability, you can play along with your favorite tunes or practice with popular "minus-one" backing tracks.