UP3 is the the worlds most advanced activity tracker. The greatest challenge, and the greatest value proposition for UP3 is the innovative sensor technology embedded into the flexible strap. UP3 can measure advanced movement and sleep patterns, and includes a bio-impedance sensor that can detect heart rate and other internal signals. Hundreds of internal component and sensor layouts were explored, resulting in different widths and lengths of the band. These prototypes, often differing by as little as .3mm, were judged for comfort, size impression, and proportions, to land on the optimal ergonomics for a variety of wrist sizes. Most importantly, the UP3 is one-size-fits-all. The clasp mechanism, uniquely designed for the UP3, allows the band to slide through a flat metal gate and lock in at just the right size for the user; this maximizes the exposure of the sensors on the skin. Combining the data from all sensors and the heart monitor, users receive detailed and accessible data about their everyday routines, empowering the user to better understand, and therefore improve their health.