it's about 1/8" thick, non-magnetic, the small holes are graduated small- large, the indented ring is off center.
Water bottle with something leaning up against it? Sorry no clue to the leaning something.
Base of a door knob?
I have no idea what this would have come from. It sreems like it is mostly plastic, the ring shape inside might have metal in it, and obviously a rusted out piece on the disc. There are no markings other than some serial number. Rang up as a half dollar.