1.100 ADJUSTABLE FREQUENCIES: State-of-the-art circuitry design with 100 adjustable frequency groups for this wireless microphone set in 500MHz band, allowing up to 30 units to use at the same time without interference. You can also enjoy the dom of changing frequency if preset frequency fails. Operating distance is up to 164 ft in open space line of sight 2.The receiver body is small and light and easily fits in the center of the palm. Powered by DC 12V, it is more convenient to use and can be carried, ideal for small outdoor events, parties, family entertainment, conferences, classrooms, karaoke, churches, outdoor weddings, etc. 3.The wireless microphone system includes two handheld dynamic microphones that deliver outstanding sound quality. Whether you're singing solo or harmonizing with a partner, these microphones meet your needs. 4.Easy to Operate: Just turn on the receiver and mics, they will match automatically. Note: It is not compatible with laptop, iPad, cellphone and AV receiver. 2 x AA batteries (not included) are required for each mic.