Old vintage Grover brass tailpiece with hanger bolt.
It may be a century old, I can’t really tell.
It’s about 1 3/8in. wide & hangs out over the banjo head about 3/4 in. It appears to have had some plating that’s wearing off. It’s got a nice patina; doesn’t look like a shiny new chrome-plated modern one.
This should look & work great on your vintage banjo.
Look at the pictures to judge it’s condition.
Thanks for looking.