The Shure Headworn Wireless System BLX4E/SM35 for singers and singing instrumentalists. It includes a Single Channel Receiver (BLX4RE), a BLX1 Bodypack Transmitter and a SM35 Performance Headset Condenser Microphone. The Single Channel Receiver (BLX4) features professional wireless technology. Plug & Play and Quick Scan make the receiver currently ready for use. SM35 Headset Condenser Microphone Features: Type: Electret Condenser Frequency Response: 40-20.000 Hz Polar Pattern: Cardioid Audio Output Level: -59.0 dBV/Pa Equivalent Output Noise: 39 dB Maximum SPL: 153.0 dB Net Weight: 72g BLX1 Bodypack Transmitter Features: Battery Life: Up to 14 hours Typical Operating Distance: 300 ft (100 m) transmission radius 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 BLX4RE Single Channel Receiver Features: XLR and ¼" output connectors Two-color audio status indicator LED Green: Normal audio levels Red: Excessive audio levels (overload / clipping) Compatible Systems per Band: Up to 12 (region dependent) Weight: 998 g Features: Manufacturer: Shure Capsule Type: Condenser Polar Pattern: Cardioid Frequency Range from (Hz): 45 Frequency Range to (Hz): 20,000 Battery Power: Yes Shotgun Microphone: Yes Switchable Pad: Yes Swan Neck: Yes Frequency Band: UHF Diversity: Yes Detachable antenna: Yes Wireless System: Vocal Warranty 2 years.