That stuff is really cool, it's called Deck Restore - Liquid Armor Resurfacer.
It's is like a high-quality outdoor latex paint with a very fine sand mixed in. It is the sort of thing someone would use to protect an outdoor wooden deck/porch from the elements.
It is intended to be walked on, so it's pretty tough stuff. But it is also easy to brush on and cleans up with water.
HAVE FUN