Sennheiser AVX Wireless Lavalier Microphone

Made with simplicity in mind, but without compromising audio quality, this self-configuring digital system handles time-consuming frequency setup and mic-level adjustments for you, so you're ready to shoot within seconds. Now, you can focus on the other critical elements vying for your attention during a shoot, and confidently record crisp, clear audio on your camcorder, DSLR, or mirrorless camera.

Resources:

Quick Start Guide

AVX Manual