I've had my eye on this fitness tracker for a while mostly because of the sheer beauty of it. I finally took the plunge and purchased it (for $120 from a 3rd party with a coupon otherwise it retails for $160) for what I think is a very reasonable price. It can be worn as a necklace, bracelet, or clip. It tracks your sleep, steps (you can add type of exercise), sensitivity to stress, your period, meditation (offers different types of meditation sessions).
You have to download an app to your smartphone and sync it as often as you like (twice a day is recommended). It's made of natural materials. No recharging required. It holds a coin cell battery which last about 6 months and is easily replaced. I've always worn it as a bracelet and have found the tracking to be quite accurate. The only downfall (which, in my opinion, really isn't a big deal) is that it doesn't sync automatically. You have to open the app and tap your leaf. All in all, I would recommend this fitness tracker to anyone as it really is a very pretty piece of jewelry that works very well!