What does UVB stand for?

Ultraviolet B

One of the three types of invisible light rays (together with ultraviolet A and ultraviolet C) given off by the sun. Although ultraviolet C is the most dangerous type of ultraviolet light in terms of its potential to harm life on earth, it cannot penetrate earths protective ozone layer. Therefore, it poses no threat to human, animal or plant life on earth.Ultraviolet A and ultraviolet B, on the other hand, do penetrate the ozone layer in attenuated form and reach the surface of the planet.