PRO D2 is a passive DI box: it has 2 unbalanced input interfaces, which are 1/4 inch (6.35mm) interfaces, for connecting musical inst ents or other unbalanced signal sources, such as electric guitars, electric basses, keyboards, etc.; there are also 2 balanced output interfaces, which are XLR interfaces, for connecting mixers, audio interfaces or other devices that require balanced signal input. The input and output are equipped with isolation to isolate the ground loop current infection. It also has a 1/4 inch Thru interface, which can send unprocessed signals to other devices, such as amplifiers on the stage, for live monitoring. Ground Lift: Used to disconnect the Pin1 mission on the DI box XLR jack, preventing current from flowing along the shield between the DI and the microphone preamplifier, thereby breaking the ground loop and eliminating noise such as caused by grounding problems. Frequency response: 20Hz - 20kHz, which can the integrity of the audio signal and enable good mission of high and low frequency signals. Input and output impedance: The input impedance is 50k, and the output impedance is 600, which helps to reduce signal reflection and distortion and effective signal mission;Attenuation (Pad): It is used to reduce the level of the input signal to prevent signal overload. The attenuation values are 0dB, -20dB -40dB. Model: PRO D2 Colour:Black Material:ABS Package Contents: 1 * PRO D2 Audio Isolator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.