This versatile box is built with Whirlwind's premium TRSP-2 transformer for optimum durability. Features a phase reverse switch which flips the polarity of Input #2. Highlights: Use fewer input channels by combining two mic lines into one. Combine two mics out of phase to remove background noise and feedback. Combine and correct phase when using a pair of mics above and below a drum. Specifications: Input Impedance: 150 Ohms x 2 Output Impedance: 150 Ohms Operating Level: -50dBu to -10dBu Freque