Wireless Portable Amplifier 1.1000channels use at the same time 2.ISO 9001:2000 3.digital frequency board 4.MOQ 30 sets Wireless Portable Amplifier,2.4g Bluetooth Digital AmplifierSpecifications1: This education system is special designed for school. When you setup for tens and hundreds of classroom, you only need to give one 2.4GHz transmitter to each teacher, whatever which room the teacher in, ...