To be honest those look quite similar to barbell weights, but isn’t a bold the object peeking in the bottom right of the picture? Is that a giant bolt?
Probably the actual barbell. Everything in the picture looks like barbell parts.

In addition to that, what is the oven story?
He probably had to heat the tools to be able to dent the barbell weights' surface. But I'd really like to see how the words look like; even if it's a single letter.
I have seen those “strongest man” competition where you are supposed to lift spherical stones, turn gigantic tires or stuff like that. News year the prize will be awarded to who will be able to print a seed phrase on those barbell weights!