... Speaker with Headset Microphone, Lithium Battery and Condenser Cartridge is Idea for Teacher, Tour Guide Product Name: Mini ... with Headset Microphone, Lithium Battery and Condenser CartridgeApplicationThis digital amplifier is ideal for teaching, assembly, conference room, church, parade ... meters. 6. With high class headset microphone, which is suitable for adorn, high sensitivity and super-cardioid ...