Shure QLXD1

20 Hz to 20 kHz frequency range with flat response (actual response is microphone dependent) Over 120 dB of dynamic range - no transmitter gain adjustments needed AES 256-bit encryption for secure transmission Up to 9 hours continuous use with two AA alkaline batteries Optional Shure SB900 lithium ion rechargeable battery provides up to 10 hours of continuous use and reports remaining runtime in hours and minutes External charging contacts for docked charging Backlit LCD with easy to navigate menu and controls Selectable display mode showing group/channel, frequency, or battery runtime 100 meter (300 feet) line-of-sight operating range 4-Pin male mini connector (TA4M) Rugged metal construction Detachable 1/4 wave antenna Frequency and power lockout