Years ago, Reevu made a bicycle helmet that had a built in rear view mirror. I purchased the helmet but the technology was not yet developed to the point where I could discard my "Third Eye" mirror. I really believe they were CLOSE and if the company could only spend more on RD, the finished product would have been excellant.

However, that never happened and the bicycle helmet was taken off the market. I sold the helmet because it was too tight being a one size fits all. I noticed they still build a motorcycle helmet.

Reevu motorbike helmets. Reevu - the world's first rear view helmet