ENHANCED SIGNAL RELIABILITY: Harnessing the power of Auto Scan, the UHF wireless karaoke microphone system rapidly identifies the least-interference frequency to sync. This advanced feature of the wireless microphone & system increases anti-interference ability and decreases interference between each channel. The wireless DJ microphone system also has lock function to lock selected frequency. 4x40 Selectable UHF frequencies allows multiset operation of up to 16 transmitters simultaneously PREMIUM WIRELESS PERFORMANCE: Quad UHF cordless mic system with selectable frequencies. Channel 1: 538.3 - 550Mhz (40 frequencies). Channel 2: 554.8 - 566.5MHz. Channel 3: 571.3 - 583MHz. Channel 4: 587.8 - 599.5MHz. The microphone wireless employs hassle-free IR synchronization to pair up the receiver and cordless mics smoothly within seconds, with minimum dropouts, and maximum feedback rejection. Long range operation for this microfono inalambrico set of 290 ft 328 ft line of sight REFINED S