So I went mountain biking yesterday with a friend, we were on an easy, rolling double track trail, I was going 30 kph or so on the big ring when I suddenly hit a fairly large rock hidden by tall grass. With no warning whatsoever I was down, I don't think I ever let go of the bars. I obviously hit another large rock with my head, the helmet took the hit. I had no concussion, just a nasty bruise on my temple. We were 10 km into the ride and I continued for another 30.
This helmet clearly saved my life or at the very least saved me from a nasty concussion.