That's a camshaft, isn't it? (and I'm sure the note also says "It's an automobile part.")

I think we should add a what tag.

[update after reading the doujin]: Ugh... I made a mistake. This whole pool deserves it.

.k1.38e+23 said:

That's a camshaft, isn't it? (and I'm sure the note also says "It's an automobile part.")

Eccentric shaft actually. I'm guessing from the same Mazda 13B engine the rotors featured on the previous page came off. It would be analogous to a crankshaft.

.k1.38e+23 said:

I think we should add a what tag.

I think you're right... Dear sweet Jesus God on a pogo stick...