The airbag inflates to cover the head in case of a crash, while avoiding the dreaded helmet hair.
Experts adapted the airbag safety concept used in cars to build the gizmo into a collar worn round the neck, 'The Sun' reported.
When sensors detect unusual body movements seconds before an accident, a helmet-shaped bag inflates around the head in just 0.1 seconds.
Designers of the Hovding collar Anna Haupt and Terese Alstin spent six years creating the device.
They said research showed cyclists wanted an "invisible helmet".
"The protection should keep the sense of freedom that goes with cycling