Shure QLXD24/Beta87A K51, Digital UHF Wireless System with Beta87A Capsule, Frequency band: K51 (606 - 670 Mhz), 24 bit / 48 kHz audio signal, AES-256 encryption for tap-proof transmission, Up to 72 MHz switching bandwidth, 22 compatible channels in an 8 MHz TV band, Switchable transmission power 1/10 mW, 120 dB dynamic range, Handheld metal transmitter with condenser Beta87A microphone capsule, Characteristic: Supercardioid, 9.5"" metal receiver, Detachable BNC antennas, Ethernet port for system monitoring and configuration, Frequency transmission via infrared interface, XLR / jack output, Transmitter operates with either 1.5 V AA batteries, or with (optional) SB 900 lithium ion rechargeable battery, Includes PS23 power supply and rack mount