This is a combined card.One side is a uv sensor card,and the other side is a LCD forehead thermometer. The sunshine which is at the upper part of the card will change color when it meets the uv light outside.You can compare the color with the color zone below to find out the intensity of the sunshine,and accordingly follow the instructions to protect your skin. The forehead thermometer,you can place the black panel close to your forehead for 10 seconds.It will indicate the body temperature.If the smiling face turns green,it means you are ok.If the green crying face comes out,it indicates you have a fever,and you'd better go to see a doctor.