What is it? A slim wristband that protects all skin types from damage caused by excessive sun exposure. The easy-to-wear strap changes colour as it is exposed to ultra-violet radiation (UVR), providing a visual warning when the user should get out of the sun or re-apply sunscreen. Why do I need this? Non-melanoma skin cancer is one of the top 10 cancers in Hong Kong and is usually caused by excessive exposure to sun during childhood, when genes in skin cells are damaged by UVR. Youngsters are particularly vulnerable because their skin is sensitive and they spend more time outdoors than adults. Sunscreen is often used incorrectly: many people do not apply it half an hour before going into the sun, as suggested, fail to apply it thickly or evenly enough and forget to re-apply it every two hours. How does it work? The strap is worn on the wrist and should be coated with the same sun cream you are using. As the UVR exposure increases, the strap changes from dark blue to brown, alerting the wearer to re-apply sunscreen. When it changes to yellow, the wearer should seek shade. One strap can be used for a full day. What's so good about it? The different colours provide an easily understood visual reminder about the sun's dangers. The straps are light and don't take up much space. They are waterproof and also act as an identification band; contact telephone numbers can be written on the back (the pack comes with a waterproof pen). And the downside? Solar Safe is an indicator only and must be used properly to be effective. The sunscreen used must have a protection factor of 15 or more and be teamed with sensible measures such as avoiding peak UVR, from 11am to 3pm, and wearing sunglasses, hats and UV-safe swimsuits. Solar Safe wristbands have a shelf life of three years and cost GBP5.95 ($82) for a box of seven and GBP19.99 for four boxes. They are available from Woolworths, pharmacies and department stores throughout Britain. They can also be ordered at www.goodforhealth.com and www.edirectory.co.uk , both of which ship to Hong Kong. See the Hong Kong Cancer Fund website at www.cancer-fund.org .