(CNN MONEY) Apple is recalling millions of power adapters because they could cause an electric shock.

Apple said on Friday the two prong wall plug adapters affected were designed for use in continental Europe, Australia, New Zealand, Korea, Argentina and Brazil.

The plugs in question were shipped between 2003 and 2015 with Macs and other Apple devices, and were also included in the Apple World Travel Adapter Kit.

In very rare cases, the adapters may break and create a risk of electrical shock if touched, the company said in a statement.

"Customer safety is always Apple's top priority, and we have voluntarily decided to exchange affected wall plug adapters with a new, redesigned adapter, free of charge," Apple said.

The adapters affected have four or five characters or no characters on the inside slot where it attaches to an Apple power cord, the company said.

Apple said it will exchange the faulty plugs at any Apple store or authorized Apple service provider.

It also said it would refund customers who may have bought new plugs because of the issue.