I bought a Hövding bike "helmet" - they call it air bags for your head - because I am vain. I also bought one for my husband, because he hates to wear a helmet. These are the main reasons why people buy this very expensive protective gear. My husband tried it on, and went straight back to the store. For him, it was much worse than wearing a helmet. At least he came back with a new helmet which he now occasionally uses.
I kept using mine. I particularly liked it when my hair was up, because I have long hair and a regular helmet doesn't fit over a bun. Today I put my hair up, put on the jacket and "helmet", reached for my keys (not suddenly. I am a sedate, middle-aged woman), and heard a loud bang. The airbag blew up while I was still standing!
They do warn that you should not walk with this, but the movement I made was something I could easily do on a bike, a soft turn, like leaning over while turning right. And if this had happened while on a bike, I would have had a real accident.
That, sadly, was not enough. My head was pushed forwards, and for a moment I was trapped in this high collar. It turned out that the airbag impacted with my bun, and pushed my head away and forwards, rather than enveloping it protectively.
I was devastated. I loved the idea of this technology, and was planning to buy it as presents for others in the family. Now I am very happy I didn't. This flaw is serious, it could cause an accident, and get me badly injured in the accident it caused.
Luckily I also have a very good looking bright red helmet, and was able to get to work almost on time.
I have lodged a complaint about this. It is not a prank, or something I post in order to ruin anything for the designers. I really wanted this to work, and have used it, expecting to be protected, for more than a year. It has also protected others I know, personally. But mine exploded for no particular reason.