Professional wireless system with 2 microphones. Ideal for professional use at any events: Karaoke, sound source recording and amplifying, vocal concerts, live-performances, conference, musical and opera, church, school, hall, family, party, etc. Specification: Receiver:Receiving system: fixed frequency by quartz controlled Receiving sensitivity:60dB S/N ratio S/N ratio: >100dB Audio output level: Unbalanced mode of CHA+B: 0 ~ 0.5V/5KΩ Unbalanced mode of CHA and CHB: 0 ~ 0.5V/50KΩ Power supply: AC 110V / 220V (±10%) Microphone: RF power output:15mW(MAX) Spurious emissions: Over 45dB carrier ware Microphone element: Unidirectional dynamic microphone Battery: Standard 9V battery AA Current consumption: About 25mA Battery life: Over 8 hours continuous operation