80 feet in the line of sight. UHF wireless microphone is less likely to be subject to interference than a VHF microphone. Reliable signal and no worried about the sound will be cut in and out during use. 3 vocalists can sing karaoke together. 1/4 input for extra wireless microphone (not included but could be found from Fifine). Separate volume control (VOL.A & VOL.B) for each wireless mic. Perfect for karaoke, party, school, and church. Adjustable echo effect. Allowed to mix the mic signal with music signal without using a mixer. The compact metal receiver has a stronger anti-interference ability than plastic ones. This cordless microphone system can save space at home and be portable for on-the-go use.