Now, it's actually really, really interesting—so in order to get the sun protection factor of any product, what you're supposed to do is on an area of skin, you're supposed to apply 2 milligrams of sunscreen, and, next to it, a control, which means there's no sunscreen on another piece of skin. And this is all done by human, like so that's all done by volunteers in all of these experiments. And then so you expose the same person—usually, I imagine, their back—to a UV lamp, and so when the sun or the UV lamp comes into contact with that volunteer's skin, the speed to which that skin burns divided by—so the one with sunscreen divided by the one without sunscreen becomes your sun protection factor. So, may I say, science has advanced, has come a really long way since we've done things this way, but right now this is still the best way that we have to measure the sun protection factor, which I found actually really, really interesting. So it's still done by a human way, we have to still just time it by sight to see when someone's skin burns—yeah, I found that extremely fascinating.