Sennheiser SKP 2000 AW-X , Professional Series Plug-On Transmitter, Frequency range: 516 - 558 MHz, Power supply with 2 1.5 V batteries, Up to 75 MHz switching bandwidth, 20 Fixed frequency banks with up to 64 compatible presets, 6 Banks of up to 64 freely tunable channels each, Pilot tone, Phantom power switchable +48 V, Output power switchable 10/30/50 mW, Four-digit battery indicator, Presets, LC display with NF level and channel display, Includes 2 1.5V batteries