Azden IRN-10 MICROPHONE A lightweight, chest worn, microphone/transmitter , it comes with an adjustable lanyard. It is both a microphone and infrared transmitter which wirelessly "links" the teacher to the IRR-30P receiver. It has a specially designed internal microphone array which provides great sound pick-up. With two switchable channels, a teacher can go from classroom to classroom with the same microphone! W ith just two "AA" batteries (alkaline or rechargeable) the microphone can be used the entire school day without recharging or changing batteries.