""...I've gotten these with Happy Meals for my kids and they are pretty much useless. One supposedly blinks slow or fast depending on the level of activity or motion. It merely blinks at  any motion, but not always and not necessarily faster with more intense activity. Battery lasts about two hours at best. The step counter just does the same thing as the blinking version but increments a number display. Unfortunately, a single "step" is often counted as a dozen or more and other times movements/step are not counted at all. Battery lasted an hour before the device stopped working completely. Most don't work at all, having dead batteries from the start.Perhaps it's the gesture that counts but these items are essentially garbage. My five year old just pretends that they are wrist-based computers/communicators."

Read more - https://www.engadget.com/2016/08/16/mcdonalds-activity-trackers-happy-meal/