Katherine Mo, a second-year student from the Department of Physics at the Hong Kong University of Science & Technology (HKUST), demonstrates how a "UV Bear", a toy equipped with a sensor to monitor ultra-levels by showing through lights of different colours, in Hong Kong August 14, 2003. By using two novel alloys developed at HKUST, UV detectors that are cost effective, portable and battery-free, are manufactured to be applied on various consumer health-care products.