This Sennheiser ew 100 wireless system includes an EM 100 receiver and an SK 100 belt pack. It operates in the B range, from 630 - 662 MHz. Note that it's not for use in the U.S. Before you buy, make sure to check your country's wireless frequency rules, as some frequencies might be illegal. Batteries aren't included. The package has a bodypack and a receiver, but no antennas or power supply. The belt - pack is missing its antenna.

How to use: First, connect your audio device to the EM 100 receiver. Then, place your audio source close to the SK 100 belt pack. Turn on the devices to start using the wireless system. Note: This system can't be used in the U.S. Always check your local wireless frequency laws before use. Since there's no power supply, you'll need to find a suitable one on your own. Also, the belt - pack is missing an antenna, so you might want to get a replacement. Maintenance: Keep the devices in a dry and clean place. When not in use, turn them off to save potential battery life if you use batteries. Check the connections regularly to ensure good performance.