1. Feedback Destroyer Used for Sound Amplifying System, 2..Verified:ISO9001,3C, 3. Manufacuturer in China Mainland. X3101 professional speaker crossover Front Side1. The Power: On/Off2. Input_A Volume indicate3. Input_B Volume indicate4. LCD Screen5.One-key shuttleReverse Side1. Analog input_A , offering XLR and TRS plug . shunt-wound2. Analog output_A , offering XLR and TRS plug . shunt-wound3. ...