... Microphone, Lithium Battery and Condenser CartridgeApplicationThis digital amplifier is ideal for teaching, assembly, conference room, church, parade, lecture, auction, sales ... howl-proof ability.3. With Audio-in function, it’s perfect for anywhere you want to listen music and programs.4. With ... Charger: DC 9V/400 MA Battery Working Time: 12-16 H Master Weight: 198 G Operation Voltage: 6-8.4VMaterial: ...