'Invisible' inflating bike helmet

(CNN) - This woman isn't leaving a costume party or "Star Wars" convention. She's wearing something called an "Invisible Bicycle Helmet."

The whole idea is to be both safe and fashion-forward.

Designers at the Swedish company Hovding hid the helmet inside a collar.

It works a bit like an airbag - inflating automatically during a crash, and expanding from the black collar you see on the left, to the helmet you see on the right.

The designers said they didn't want to be seen wearing the typical hard plastic and foam helmets. So they came up with this with help from a brain-trauma specialist.

But the trendy helmet comes at a cost - $600, or about the same as a 32-gigabyte iPad.