Fibit's Alta HR is its smallest tracker to feature a continuous heart-rate monitor.
Fitbit's Charge 2 is an easy to recommend fitness tracker for those after a bit more than the "basics" and a healthy dose of motivation. Continuous heartrate monitoring, an amazing companion app, and a five to six day battery life are all standout features. On the other hand, the lack of water resistance and a somewhat bulky design may put some off.