The Shure BLX14/SM31 Headworn Wireless System is part of the Headworn wireless systems family.Shure BLX® Wireless Systems combine professional-quality sound with simple setup and an intuitive interface for legendary audio performance right out of the box. Precision-built and available in a variety of configurations, it’s the most accessible way to own the stage.Shure BLX14/SM31-H9 Includes: BLX4 wireless receiverBLX1 bodypack transmitterSM31FH headset microphonePower supplyClothing clipWindscreensUser guideShure BLX14/SM31-H9 Features: BLX4 single-channel receiver: XLR and 1/4" output connectors Microprocessor-controlled internal antenna diversity Two-color audio status indicator LED: Green: Normal audio levels Red: Excessive audio levels (overload / clipping) BLX1 bodypack transmitter: Quick and easy receiver frequency matching TQG connection for use with Shure lavalier, headset, earset and instrument microphones and guitar cables Easily accessible On / Off switch SM31FH headset microphone: Wireframe headset fits securely and comfortably for fitness and aerobics instructors Moisture-repellent hydrophobic fabric protects the microphone cartridge from harmful corrosion that occurs in humid environments Flexible gooseneck provides discrete adjustment capabilities to optimize placement for greatest isolation Lightweight and low-profile design won’t fatigue instructors during high-impact use TA4F (TQG) connector is compatible with any Shure wireless bodypack Tailored frequency response ideal for crisp, clear vocal reproduction Available with bundled BLX and GLX-D wireless systems Legendary Shure precision engineering for durability and performanceShure BLX14/SM31-H9 Specifications: BLX4 single-channel receiver: Compatible Systems per Band: Up to 12 (region-dependent) BLX1 bodypack transmitter: Battery Life: Up to 14 hours Typical Operating Distance: 300 ft (100 m) transmission radius SM31FH headset microphone: Type: Electret Condenser Frequency Response: 45 Hz – 20 kHz Polar Pattern: Cardioid