Bogen TBL1S Transformer Balanced Aux Input Module (for Bogen Matrix Systems)Bogen's advanced plug in modules provide a wide range of functions to support a variety of applications. These modules support different signal source requirements, including the ability to interface to balanced and unbalanced high and low level inputs, stereo or mono, telco systems, and microphones. Features: Transformer isolated line level input Gain Trim control Bass & Treble controls Gating w Threshold & Duration Mute send & receive Variable