I tried Fitbit's sleep tracking feature Premium Sleep Profile for two months
Review: Fitbit Charge 2 (and my 2017 goal: walk more!) | The Hiking Photographer
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Fitbit Charge 2 Health Fitness Tracker Smartwatch wristband Sports Watch with Sleep Monitor,Heart rate pedometer,Calorie Tracker For Men And Women Couple Watches - Black/Purple/Blue/Cyan | Lazada PH
What I Learned from Tracking My Sleep with Fitbit for Two Months — International Sleep Charity