According to the light sensor of your watch, we can provide you with sun protection advice. To run this software, your watch must have a light sensor. If your device does not have a light sensor, we do not recommend that you download this app. Note: some manufacturers have disabled the third-party developers to call the light sensor. Please check with your manufacturer to confirm that your watch supports the third-party developers to call the light sensor of your watch before purchasing.If your wrong purchase causes the equipment to be unable to use the software, we will not refund.