SunFriend
SunFriend, the world's first wearable monitor for healthier, safer sun time is a durable, waterproof (up to 3 metres) wristband that helps you to enjoy the health benefits of sunshine and increase your vitamin D levels without the worry of over-exposure.
Simply set your skin colour or sensitivity - 1 is for the lightest, and/or most sensitive skin and 11 is for the darkest, and/or least sensitive skin - and SunFriend will keep track of your real-time UV/sun exposure.
SunFriend's LEDs flash when you have had enough healthy exposure to the sun, letting you know when it is time to cover up, go inside or wear a premium sun block.
SunFriend.com