It's grease.

But seriously, it is a little weird. 99% will wipe off of your hands with paper towel. Any soap is good enough for total clean up. NO smell whatsoever. The tube tip applicator makes it easy to use.

To my surprise though, it being clear is actually a drawback during assembly, because it's hard to see if you've applied enough. It is truly CLEAR. I'd never considered that. Placing individual loose balls is weird too because the background for the shiny steel balls is a shiny steel race, instead of a colored bed. It's a little bit of an eye teaser.

Seems to work just fine. Quiet and smooth. The temps here have dropped a lot so I can't give it a "heat test", although I tried.