Despite its powerful array of metrics and tools, this tiny tracker doubles up as a chic fashion accessory; designed to go with any look. When inactive, the Vívosmart 3 turns off its display, allowing it to blend in. However, when operational, this device is capable of monitoring advanced fitness and wellness data, such as fitness age and stress levels. It monitors heart rates all day, whether you’re running, swimming or sleeping, and can last for 5 days without being recharged. This beauty is also available in two sizes, in a choice of four colours.