Nearly a week after pulling them from Happy Meal packages — and subsequently erasing all trace of their existence from stores — McDonald’s has issued a formal recall of all 29 million Step-It fitness trackers over reports of skin irritation and burns.

According to the official recall notice posted with the Consumer Product Safety Commission, McDonald’s knows of at least 70 complaints of skin irritation, including at seven incidents in which wearers of the trackers developed blisters.

So the company has decided to recall all Step-It trackers handed out between Aug. 9 and Aug. 17 in the U.S. and Canada.

There were two versions of the tracker: The “Activity Counter” model came in orange, blue or green and features a digital screen that tracks a child’s steps or other movement. The “Light-up Band” version was made with red, purple, or orange colored plastic and blinks light with the child’s movement. Both styles of activity wristbands have a square face with the words “STEP-iT” printed on them and a button to depress and activate the wristband. The back of the square face contains the etched words “Made for McDonald’s.”

If you have any of the McDonald’s Step-It bands, the fast food chain is asking you to return them immediately to any McDonald’s where you’ll receive a free replacement toy and either a yogurt tube or bag of apple slices.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.