Bioelectronic healthcare company electroCore LLC said on Tuesday that the U.S. Food and Drug Administration had approved its hand-held device to treat cluster headaches.

Cluster headaches are an extremely severe form of headache, in which the pain is usually limited to one side of the head and generally recurs over a period of several weeks. The pain is typically described as burning, stabbing, boring or squeezing, and may be located near or behind the eye.

ElectroCore’s device, gammaCore, aims to treat the condition by applying a mild electrical signal to the vagus nerve through the skin. The company anticipates the product will be available in the United States in the third quarter.

The device, which can be self-administered, is already approved for use in South Africa, India, New Zealand, Australia, Colombia, Brazil, Malaysia and Canada.

Around 350,000 people in the United States suffer from cluster headaches, the company said.