Whirlwind Qbox is a versatile audio testing device that combines a signal source with a monitor amplifier. It features a balanced output with a selectable 440 Hz sine wave oscillator or an internal electret condenser microphone. The output level can be set to +4dBm, -20dBm, or -50dBm. The monitor section has a balanced input with up to 60dB of gain and a built-in speaker. It also includes a 1/4" TRS headphone jack that disconnects the speaker when utilized.