The Sennheiser EM 100 G4 is a true-diversity, half-rack wireless receiver housed in a rugged, full-metal chassis and compatible with the SK 100 G4 bodypack transmitter and the SKM 100 G4 handheld transmitter. It offers high-quality, reliable audio to presenters, clergy, lecturers, and performers working in business and educational settings, houses of worship, theaters, or on musical stages.