How do aero cycle helmets work?

Answer 1

They work by making the head a bit more aerodynamic, making it slip easier through the air. With less wind resistance you get the same speed at less effort, or more speed at the same effort as if you didn't wear a helmet.

And some of them are tested to the same level of impact protection as regular helmets,which can reduce the risk of injury in case of a crash or a fall.