What the heck is this

[berkshire mike]

 

[berkshire mike]

 

[Older The Better]

Complete shot in the dark but looks like a fake keyhole in the pattern, maybe a lock cover?

 

[A2coins]

Head scratcher

 

[creskol]

It may be a clock pendulum weight

 

[Reanm8er]

The recesses could be a means for removing it from whatever it fit into. Similar to the back of a watch.

 

[glass half fool]

I agree with Reanm8er .It is a guess on my part but the underside makes it look like the slots are there to help remove it from what it is mounted to

 

[Tony in SC]

I'll also go with pendulum. I have one kinda like that snaps onto the adjuster.

It may be a clock pendulum weight

 

[CRUSADER]

It may be a clock pendulum weight

me too