Features: DIY digital power standing waves meter, small and portable, built in rechargeable battery, no external power supply. SWR meter can directly display forward power, reflected power, antenna power, antenna efficiency, standing waves, battery voltages. Red light is displayed when charging under power on, green light is displayed when full, yellow light is displayed when undervoltages. Digital standing waves meter accuracy meets the needs of amateurs, highs standing waves, battery undervoltage buzzer alarm function. 0.5W120W (up to 200W, below120W long term test recommendedFM, AM, CWmodes, SSBmode optional), one touch display, modes switching function. Specifications: Material:Metal Frequency ranges: 1.8mhz-50mhz Measurement ranges: 0.5w-120w (up to 210W, long-termFM, AM, CWmodes, recommended less than 120w, SSBmodes optional) Measurement accuracy: