The BOYA BY-BM3032 is a super-cardioid shotgun microphone for cameras, camcorders, and audio recorders. With powerful functions, it helps you to gather the clear & natural sound during professional application. High-Pass Filter for Rejecting Low Frequency Noise With a three step High-pass Filter, BY-BM3032 makes it available to reject low frequency noise, such as ambient noise, air conditioning noise, and traffic noise lower than 75Hz or 150Hz. Automatic Power ON-OFF Function Provides More Convenience Automatic Power ON-OFF Function brings more convenience for users. Long press the power button to active the automatic power function, and the BY-BM3032 will be consistent with the on/off state of your camera, which helps saving the battery life in case you forgot to turn off.