Dosy CB Ham Radio SWR Watt Meter TC-4001P Test center Measures Modulation Percentage, Antenna SWR, and SSB Modulation Reads RMS and Peak Power, Four watt ranges: 0 - 20, 0 - 200, 0 - 2000 and 0 - 4000 Dosy Professional Architecture with AC/DC Power Supply Built in phone jack for signal monitoring Large 4 1/2 inch Backlit Meter