REASSURING SHOPPING: We offer friendly policies and timely customer support in line with . Please don't hesitate to reach out - all questions will be answered within 12 hours. OUTSTANDING STAMINA: Each wireless mic is powered by two 1.5V AA batteries (not included) with a stamina of up to 6 hours. You can use rechargeable batteries while having AA batteries as a backup. EXCELLENT SOUND QUALITY: Superior dynamic cartridges are used in the 4-channel wireless microphone system for comprehensive range frequency response. They perform well in both singing and speaking. SOLID AND DURABLE: The wireless mic system comes with 4 wireless mics fully metal made. The receiver is well-designed in metal boxes for professional & home frequent use. Superior materials are used. EASY OPERATION: The SG-400 is easy to use with a separate control knob and LCD section for each channel. The Unique ID Pilot technology prevents the 4 wireless microphones from interfering each other. POWERFUL FUNCTIONS: The 4 mic wireless system has necessary functions such as Auto-Lock, Volume Control, Mute, and Battery Indicator. The mics and the receiver shows important info with LCD screens. STABLE TRANSMISSION: The UHF wireless microphone system has 260 frequencies - the Auto-Scan selects the best automatically for each wireless mic for the best transmission in different circumstances.