A standing wave measuring bridge belongs in every amateur radio shack. The adjustment of an antenna can change over time, for example due to aging or breaking of an element during a storm. To protect the station you should therefore always keep an eye on the standing wave ratio (SWR) of the antenna.
WiMo offers SWR meters from various manufacturers. The most important selection criteria are the frequency range and the maximum permissible power. Instruments with a cross pointer are easier to read, instruments with a switchable instrument are often more precise. In some cases there are measuring bridges with two sensors to allow short wave and FM to be connected simultaneously.