Shure ULXD2 Digital Handheld Wireless Transmitter with Beta 58A Microphone 30 Hz20 kHz range with flat frequency response (actual response is microphone dependent) AES 256-bit encryption for applications for which secure transmission is needed Proprietary Shure Gain Ranging optimizes the systems dynamic range for any input source, eliminating the need for transmitter gain adjustments Shure Lithium-Ion rechargeable battery pack provides over 12 hours of battery life, precision metering in hours and minutes with 5 segment battery fuel gauge, and zero memory effect Rugged metal construction