To protect against both UVA and UVB rays, make sure you choose a broad spectrum sunscreen, and other measures of sun protection such as sun protective clothing, hats, sunglasses, and seek shade.
In the United States, sunscreen is regulated by the FDA, and classified as being an Over The Counter (OTC) Drug.
A sunscreen with only a SPF rating and no broad spectrum means that you are only protected from the UVB (burning) rays, and not the UVA (aging and tanning rays)
The difference between UVA, UVB, and UVC rays and how they affect us. UVA rays penetrate deep within the skin, causing aging and tanning. UVB rays cause burning.