The EQ5 requires a separate USB power supply. Do not use a computer's USB port or share a power source with the audio source, as this will cause ground noise. The front and rear RCA inputs and the 3.5mm AUX input are connected in parallel. Both inputs and outputs will operate simultaneously. Therefore, do not connect the RCA and 3.5mm AUX inputs simultaneously to avoid signal mixing. The EQ5-PRO can bypass audio signal input and output in a bypass mode without a power supply, but the signal will not be pre-amplified, and the VU meter will not function. Due to different batches, there may be differences in product appearance, color, and printed text, which will not affect the use. Color: Black Material: plastic Package Contents: 1*Equalizer 1*USB cable