They look like a set of fancy headphones.
But a set of spikes inside the band act as electrodes to stimulate the brain.
According to California startup Halo Neuroscience, the device can help improve the performance of athletes, pilots and surgeons, and potentially help rehabilitation for stroke victims.

"The brain is an electrical organ," said Daniel Chao, a physician and co-founder of Halo, in discussing the product at this week's Fortune Brainstorm Tech conference.
By stimulating the motor cortex, Chao says the Halo device can "extract latent potential" in the brain to improve performance for people who rely on making quick decisions on movements such as athletes.
"We think of athleticism athletes, pilots as athletes."
Halo, which has raised some $10 million in funding, began selling the Halo Sport device last year for $749.
The San Francisco startup has also concluded deals with the San Francisco Giants baseball team and the U.S. Olympic ski team to integrate Halo in training programs.
Chao said the U.S. military is the company's largest customer, aiming to help improve the performance of special operations team
Users are advised to wear the headset for 20 minutes a day, to get electrical stimulation "to build stronger, more optimized connections between your brain and muscles," according to the company website.
Chao, who trained as a doctor and studied neuroscience at Stanford, previously worked at a startup called Neuro Pace which uses electrical stimulation to treat epilepsy.
He said his research found little help from drugs for the disease and decided to study "electricity as medicine for the brain."
Chao said he hopes to obtain U.S. government approval to use the technology for medical applications.
"As a doctor I want to see this achieve an FDA (Food and Drug Administration) approval," he told the conference. "The first application could be for stroke rehab."