I spent 30 days wearing Google’s $99 Fitbit Air—it only let me down in 2 waysGoogle’s affordable wearable tracks sleep, heart rate, blood oxygen, and workouts remarkably well, but buyers should understand where it falls short before purchasing.This Week The Trend·3d ago·6 min readGoogle’s Fitbit AirFitbit AirOura RingRing 3 or 4