This Sennheiser ew 300 IEM G3 wireless in - ear monitor system is a great choice for audio enthusiasts. However, it doesn't come with a power supply. The system includes an SR 300 IEM G3 stereo transmitter and an EK 300 IEM G3 bodypack diversity receiver, operating in the 516 - 558 MHz frequency range. Before you buy, make sure to check your country's wireless frequency regulations as some frequency ranges may be illegal in certain countries. Also, note that the transmitter doesn't have an antenna, and the belt clip is missing.

Using this Sennheiser wireless in - ear monitor system is straightforward. First, connect the necessary devices to the transmitter and receiver. But remember, you'll need to provide your own power supply as it's not included. When using, check the 516 - 558 MHz frequency is legal in your area. Regarding maintenance, keep the system clean and store it in a dry place. Since the transmitter has no antenna, make sure to attach a suitable one if needed. And because the belt clip is missing, you may need to find an alternative way to secure the bodypack receiver on your body.