Shure BLX4 Single Channel Receiver - for use with BLX Wireless Systems, Transmitter Sold Separately | H11 Band (BLX4=-H11)WIRELESS FREQUENCY BAND SELECTION - Before purchasing, please ensure that the wireless frequency band you select works in your area (refer to Shure website for details > search Shure Wireless Frequency Finder).COMPONENT ONLY - For this BLX4 wireless receiver to work, please make sure it matches the frequency band (e.g. H9, H10, J11) on your Shure BLX series transmitter (BLX1 or BLX2), sold separately.SUPERIOR AUDIO - Get the show going with no strings attached. Professional Shure sound for every band and any vocal need.EXTEND THE STAGE - The system operates up to a range of 300 feet (100m), so you can take the show into the crowd without interruption.QUICK & EASY SETUP - A breeze to setup and operate, BLX will have you up and running in record time. BUILT-IN VERSATILITY - An impressive variety of Shure microphones are available in BLX systems, so you can find the sound that works for you.BATTERY LIFE - BLX transmitters get up to 14 hours of power from a single pair of AA batteries, so the show can go on and on (and on).WHAT'S IN THE BOX - BLX4 single-channel receiver, power supply, and user guide. Free 2-YEAR WARRANTY included.