The Merlin ActiFit Go is a narrow tracker with broad offerings. The device has a built-in heart rate sensor, which provides information in real time. It offers a 2-minute fatigue test and can be adjusted to 6 types of workout, from walking to mountain climbing, tracking steps, distance travelled, calories burned and sleep cycles. The ActiFit Go not only displays progress towards daily goals, but smart notifications, with statistics automatically synced to any smartphone.