Stringline Clamp. It’s called a Stringline Clamp.
What’s it used for? It’s used to setup a stringline for a concrete (curb in this case) paving machine. The stringline is what the machine follows to lay the curb. There are a lot of videos online of the machines working, but not many that show the line.
Since I found it 50 feet off the street, I’m assuming when my neighborhood was built in 1981, they broke it and just threw it.
I also unearthed pieces from at least three 750ml bottles from the same area. I’m pretty sure I know why they were discarded. :)
This is the reply I got from the company.
I found this in my back yard while tilling a few weeks ago.
It’s about 4" in length, cast of (I think) lead.
I have sent these photos to the manufacturer, so I’m hoping to here back from them about it’s specific use, and what it was a part of.
I have my theory on how it ended up 2-3" deep in my back yard, but I will wait until I get answers before I share.