Detail of the insulator string (the vertical string of discs) on a 275,000 volt suspension tower near Thornbury, South Gloucestershire, England, United Kingdom.  The small pairs of black weights hanging from the line near the insulator are "<a href="https://en.wikipedia.org/wiki/Stockbridge_damper" class="extiw" title="en:Stockbridge damper">Stockbridge dampers</a>"; they prevent the aeolian vibration that causes the wires to "sing" in the wind.
Adrian Pingstone
Photo taken by uploader