The UV light, which is responsible for tanning and is divided into 2 categories: UVA or UVB.
UVA’s main role in the tanning process is oxidizing melanin, the browning pigment that tans the skin. UVB triggers melanin production in the skin. Both types of UV rays play a significant role and are needed for a balanced tanning process.
Most tanning equipment is designed to replicate the UVA and UVB produced by the sun, while allowing you to control your exposure.