The Solar Safe UV Sun Monitor Wristbands make sun block application easier. Before heading out into the sun, put on one of the wristbands and apply sun block lotion to your body and the wristband. When the wristband begins to lose color, it signals the need to apply more sun block. If the wristband loses all its color, it is time to seek shelter from the sun before you develop sunburn. These wristbands take all the guesswork out of when to reapply sun block, or when to call it a day, allowing you to just focus on fun in the sun.