Shakespear ART-3 is a compact and easy to use standing wave meter. You can measure both the output power (watts) of your onboard VHF radio, as well as the antenna efficiency (VSWR) of your antenna. Thanks to the internal battery, the Shakespear ART-3 can be used as a mobile device, or it can also be connected to a 12V DC power source using the supplied power cable. From now on you will no longer have any doubts on board: VHF not working or system badly??? Thanks to the Shakespeare Rosmetro ART-3.