Nearly 4 million BowFlex adjustable dumbbells are being recalled because the plates can dislodge and cause injury.

Johnson Health Tech Trading has voluntarily recalled over 3.8 million sets of the BowFlex 552 and 1090 Adjustable Dumbbells. Here’s how to receive a replacement unit.

More than 300 reports of the weight plates becoming dislodged have been filed, with more than 100 of those cases resulting in injuries, the U.S. Consumer Product Safety Commission said.