Features With Clear Display: Equipped with a large 1.29 inch screen, this SWR counter with 5 display modes can switch between normal mode and peak hold mode. The alarm function: intermittent sound alarm for standing wave ≥ 2.0 and continuous sound alarm for standing wave ≥ 3.0, very reliable. SUPERIOR ACCURACY: Combining the detector diode adjustment algorithm and medium high-speed detection mode, the accuracy is better than ±5%. RECHARGEABLE USE The 3.7V rechargeable lithium battery inside has a large capacity of 900mAh, which supports a long working hour up to 90 hours. Convenient Carrying - Comes with compact size and light weight, the standing wave protractor is very convenient to carry. Specification: Item type: SWR counter Frequency range: 1.6-50MHz. Power measurement range: 0.5W-200W Standing Wave Measuring Range:1.0-99.9 Insertion loss: <0.12dB Standing wave insertion: ≤1.02 to 1.6-30MHz ≤1.05-30-50MHz Measurement accuracy: better than ± 5% Impedance: 50Ω Standing wave alarm: when the standing wave is ≥ 2.0, an intermittent audible alarm will be activated. When the standing wave is ≥ 3.0, a continuous audible alarm will be triggered. The alarm clock can be turned off. RF interface type: so239 Display content: direct power, standing wave, antenna end power, efficiency. Power supply: Built-in rechargeable lithium battery or USB type C Battery Type: 1 x 3.7V 900mAh Rechargeable Lithium Battery Comes with built-in battery. Power consumption: <0.1uA Screen size: 1.29 inches. Screen Type: Organic Light Emitting Diode Data communication: USB Type C Firmware Upgrade: Support Product dimensions: approx. 88 x 38 x 64 mm/3.46 x 1.5 x 2.52 inches, excluding projections. Package list: 1 time ROS counter Note: Exceeding 500W may damage the detection components. Package List 1 x SWR Meter