Signstek Professional USB Port or Battery Operated LCD Digital SWR (Standing-Wave Meter) & Po4wer Meter VHF 125-525MHZ 120W for 2 Way Radios Forward/Reversed/VSWR ration in one push button. LED backlight display for easy reading. Powered by Applicable rechargeable AAA batteries battery/external USB port. Micro USB-DC 5V output (not include adapter). Convenient control layout for ease operation. This SWR &amp; power meter is a highly accurate RF meter for measuring forward power and VSWR. RS-50 SWR &amp; power meter can read out directly without any calibration. RS-50&#039;s maximum measurable power range up to 120W. Low insertion loss(0.3dB or lower) structure allows it to be connected permanently. Frequency range:125- 525MHz(this applies to: 136-174MHz/400-470MHz) Measurable power range:0 - 120W(in the V:140-150MHz U:430-440MHz range) Maximum power:120W Accuracy:AVG +/- 5% Impedance:50 Connector:M-J(So-239 (M)) Power1.5V hydrocarbon battery/ 1.2V rechargeable battery/ External USB port(Connect DC 5V Adapter) Dimension:70WX 78H X 30Dmm Weight:220g 1, Apply output of transceiver to &#034;TX&#034; and antenna or load to &#034;ANT&#034;. 2.&#034;POWER&#034; on for ready to use. 3.LCD display show simultaneously &#034;Fwd/Rev Power and SWR&#034;. 4.For back-light, please switch &#034;LIGHT&#034; to &#034;ON&#034;. 5. No function in 30 seconds, the backlight will automatically off. 6. Once PTT launched, the backlight will be back. 1.Remove the black screw from the cover to open the rear panel. 2.Install 2 pcs &#034;AAA&#034; batteries. 3.Can be used with alkaline or Ni-Ca, Ni-MH rechargeable battery. 4.This unit has no built-in charging circuitry. 5.Be sure to correct polarity of battery. 6.Remove the battery if the unit won&#039;t be used in long period.