A helicopter headset serves the same purpose as any other aviation headset, but it is often wired differently. Helicopter headsets usually come with a coiled cord and a U174 military/helicopter plug. The coiled cable is more flexible, and the cord does not whip about the cockpit or get tangled up, especially given that many helicopters have jacks installed in the cockpit ceiling.
Helicopter pilots also sometimes wear helmets with build-in headphones instead of regular headsets.