The Federal Trade Commission on Tuesday approved the $9 billion merger of Panasonic Corp. and Sanyo Electronic Co. — on one condition.

To satisfy the FTC’s anti-competitive concerns, Sanyo must sell its portable nickel metal hydride (NiMH) battery business, including a manufacturing plant in Japan. The two companies are the world’s largest makers of such batteries, which power products including two-way radios used by police and fire departments throughout the United States.