Roland WPM-10 Wear Pro, Stereo In-Ear Microphone, For the GoPro HERO3, HERO3 + and HERO4 cameras, Binaural recordings in 3D stereo sound, Powered by GoPro camera (no batteries needed), Open design, Type: Electret condensor, Frequency range: 20 - 20,000 Hz, Sensitivity: -33.5 dB (0 dB = 1 V / Pa 1 kHz), S/N