Long-wavelength light, like red light and near-infrared light, has this amazing ability to penetrate through tissues, including your skin. And so, if we were to shine red light or near-infrared light onto your arm, it would pass through that top layer of skin. It might impact it a little bit, but it could penetrate deeper into your skin, not just to the skin layers, but maybe even down to the bone—maybe even down to the bone marrow.