There is a long, thin, rubber-y line wrapped around/connected to the water line pictured below.
Other angle:
The piece in question is loosely hanging via a zip tie on my main water line about shoulder height and can be moved up/down easily.
They send someone every month here. A guy comes down the street looking at all the meters (they are under metal plates in front yards) and putting info into a phone. I guess the city has an app. He has a metal pry bar with a long handle he uses to open them