Wireless MIC for Teacher 1.Features:hand free,USB jack 2.Certificate:ISO9001: ... 4.laser,page up/down Wireless Microphone for Teachers,USB Wireless Microphone,Bluetooth Wireless Microphone Feature:1.Portable,convinient,microphone hands free,USB jack2.Certificate ... MIC.8.Lithium Battery Environmental protection.9. It can work for 30 hours,standby time :60 days.More specifications: Transmitter(Holding ...