Power lines in the U.S. operate anywhere between 69 kV and 765 kV, depending on the grid system they belong to. The voltage might seem like a lot (and it definitely is), unless you compare it to a ...

Metal bellows are a reliable alternative to springs in such applications. To increase conductivity, a layer of gold is plated over the bellows to ASTM B488.

Post this The metal springs market was valued at US$ 20.6 Billion in 2016 and is expected to grow at a CAGR of 5.1% during the forecast period from 2017 to 2025.

When the metal spring (it looks like an elongated door stop) touches the curb, you hear and feel it to keep from parking too close and rubbing your tires against the concrete.