Designed for Fitness Instructors, Hydrophobic Fabric Protects Mic, Flexible Gooseneck, Cardioid Polar Pattern, Includes Windscreen The SM31FH Fitness Headset Condenser Microphone from Shure is a cardioid condenser headset microphone designed to be used by fitness and aerobics instructors. It has integrated moisture-repelling hydrophobic fabric that helps protect the microphone capsule from sweat and humidity. A windscreen is included.