Quantum II is a completely self contained sound system for use in the classroom or similar environment. It is equipped with a powerful 30 watt amplifier and two infrared receiversto facilitate simultaneous use of two wireless microphones. In addition, it features an auxiliary line level input, vocal clarity control and a variable line level output. The Quantum II system includes: Built-in infrared sensor for full 180° reception Auxiliary line level input for DVD, computer, video projector, VCR, iPod®, or other media device. Efficient full range speaker Two external sensor inputs for additional infrared coverage External speaker output (8 ohm) for companion speaker