Stockbridge dampers
... that the dumbbell-shaped devices commonly seen on overhead power lines are Stockbridge dampers, used to suppress wind-induced vibrations?
... that the <a href="./Dumbbell" id="mwDYI" rel="mw:WikiLink" title="Dumbbell">dumbbell</a>-shaped devices commonly seen on <a href="./Overhead_power_line" id="mwDYM" rel="mw:WikiLink" title="Overhead power line">overhead power lines</a> are <b id="mwDYQ"><a href="./Stockbridge_damper" id="mwDYU" rel="mw:WikiLink" title="Stockbridge damper">Stockbridge dampers</a></b>, used to suppress <a class="mw-redirect" href="./Aeroelastic_flutter#Flutter" id="mwDYY" rel="mw:WikiLink" title="Aeroelastic flutter">wind-induced vibrations</a>?