Best Brass e-Sax - electronic mute system for tenor sax with 3-mode digital echo function, 3.5mm input jack (allows an external sound source to be combined with the signal coming from the mute or microphone), 3.5mm output/phones jack (allows the system to be connected to earphones for private practice, external sound system or to a recording system), lightweight, compact size, very silent (approximately 69 - 89dB).