Wear it to go

Smart rings are best used for fitness tracking, and the Fittr Hart X2 delivers this with a laser-sharp focus

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The Fittr Hart X2 is available in sizes ranging from 6 to 13, and in three colours - black, gold, and silver. I'd suggest going for the black option; it looks the most subtle and understated. The ring itself has a titanium shell with a scratch resistant coating, and comes with a charging case which itself has a battery.