 So when it is wintertime, you might say, I never want to take vitamin D. And during the winter or the summer, I don't. I get outside and you can set it on your phone. Are you in your swimsuit? Are you in shorts and a t-shirt? Are you in long pants and long sleeves? It allows you to put in how much of your skin is exposed. What time of day is it? Is it overcast or not? And then when you look at the different, I forget the grading systems of skin type.