Sun Bum SPF 30 3oz Baby Bum Natural Sunscreen. A baby's skin is very different, so we made a different kind of sunscreen for them. Babies have a lot thinner skin and their body's natural protection system is still developing, so extra special care and consideration must go into protecting them from the damaging effects of the sun. That's why we developed a premium naturally sourced sunscreen for our kids and friends with super sensitive skin. This is the cleanest, most natural protection me make.