This product is a short band LED light indicating SWR meter. Powered by RF-tapped power, no batteries are required, and easy to carry. SWR meter is a device used to measure radio frequency signals using 5 LEDs to indicate the strength of the signals, with different colors to indicate different ranges of SWR. It is used to measure and display the SWR of shortwave radio signals in the frequency ranges of 3-30MHz. Input power does not exceed 100W, the smallest LED (andgt 1.0 corresponds to the green light) light requires 5W power, suitable for a variety of shortwave radio equipment. Features: Compact and lightweight, powered by RF-tapped power, with no batteries required, and easy to carry, very suitable for amateur radio enthusiasts to use in the field. It can be used to measure radio frequency signals, it uses 5 LEDs to indicate the strength of the signal, with different colors of LEDs to indicate different SWR ranges. It is used to test the SWR of shortwave radio signals in the frequency ranges of 3-30MHz. The input power does not exceed 100W, and the smallest LED (andgt 1.0 corresponding to the green light) light requires 5W power, suitable for various shortwave radio equipment. This equipment is commonly used in radio communication systems such as radio broadcasting, television broadcasting, and radio communication. It helps the operator to determine the strength of the signal and thus adjust the settings of the radio equipment, to improve the quality and reliability of the signal. The entire circuit has no component that need to be adjusted and will work properly as long as the connections are correctly. IN is the RF input and OUT is the RF output. The IN terminal connects to the radio ANT and the OUT connects to the antenna. It can be used without any calibration and adjustment in the shortwave ranges, which is very simple and convenient for the DIY hobbyist. Specifications: Name: SWR Meter Material: metal Using frequency: 3-30MHMz Maximum power: no more than 100W Insertion Loss: andlt 0.3dB VSW: andlt 1.2 Interface: M female Item size: 25 x 25 x 50mm or 0.98 x 0.98 x 1.97in (not counting M base) Package size: 80 x 30 x 50mm or 3.15 x 1.18 x 1.97in Package weight: 85g or 3.00ounce Packing List: 1 x SWR Meter