Bellabeat Leaf $119 (about £90)

Some smart trackers have masqueraded as pieces of jewellery for a while now, but the female-focussed Bellabeat Leaf is actually aimed at women’s health as well. Bellabeat has built the Leaf to complement women’s lifestyles, making the device wearable as a bracelet or a pendant, tracking sleep, steps, calories and periods either way. Leaf has no screen, like many other fitness bands, so all the data gathered is displayed in its iPhone app, which offers a chance to see your goals and stats, but don’t expect the kind of depth seen in a Fitbit.