The shortwave automatic antenna tuner contains a set of 7 capacitors and 7 inductors, which allows it (with the largest configuration) to work effectively in a wide frequency band, overlapping the amateur radio HF band of 1.8-55MHz. Built-in lithium battery, 3.7V, 1500mAh, you can use Type-C cable to recharge it. Equipped with 0.91inch OLED display, you can see the data clearly. Automatically tuned and do not need control wires, suitable for most radio stations. You can have a try. The shortwave automatic antenna tuner contains a set of 7 capacitors and 7 inductors, which allows it (with the largest configuration) to work effectively in a wide frequency band, overlapping the amateur radio HF band of 1.8-30MHz. Made of quality material, wear resistance, with stable and reliable performance. Built-in lithium battery, 3.7V, 1500mAh, you can use Type-C cable to recharge it. Equipped with 0.91inch OLED display, you can see the data clearly. Automatically tuned, no human and control wires are required, and it is suitable for most radio stations. One button to on/off, easy to use very convenient. Connect the radio, ATU antenna tuner and antenna. For the first use, please set the output power of the radio or power amplifier between 20-30W, or the high-power tuning can easily damage the antenna tuner. Set the radio mode, use frequency modulation mode. Choose the antenna band to use, use 20-30W power in frequency modulation mode, the radio PTT, observe the PWR and SWR of ATU antenna tuner. ATU button TUNE use: short (less than 1 second) ATU button, it is in reset state, long (more than 1 second) ATU button is in tuning state. If the SWR display of the ATU antenna tuner in the transmitting state is 2.0, it means that the antenna is detuned.6.You need to use an antenna tuner. and hold the ATU button tune to tune and observe the SWR value. If the SWR is 3.0 after tuning, the antenna be detuned. In serious cases, it is not recommended to use more than 30W power, and the transmission power should be controlled below 30W; If the tuning is completed, the SWR display is less than 2.0, and the maximum power of 100W can be used for transmission. Name: ATU100 Tuner Display: 0.91inch OLED display Charge: USB Type-C cable Battery: 1 * lithium battery, 3.7V, 1500mAh (included) Voltage: typical + 12 V (DC10-15V, 13.8V) Working frequency: 1.8-55MHz Maximum current consumption: 400mA Maximum working power: 100W Maximum possible measurement power: 150W Minimum power required to starts tuning: 5W Minimum possible measurement power: 0.1W Measurement step for power up to 10W: 0.1W Measurement step with power higher than 10W: 1W Power measurement accuracy: 10% Maximum installation inductance: 8.53uH Minimum installation inductance step length: 0.05uH Maximum installation capacitance: 1869pF Minimum installation capacitance step length: 10pF Number of panel buttons: 3 (ON/OFF, AUTO, TUNE) Item size: 160 x 90 x 40mm / 6.30 x 3.54 x 1.57in Item weight: 413g / 0.91lb Color: Black Material: Metal+Plastic Package Contents: 1 * Antenna tuner 1 * USB cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.