I purchased a batch of 5 Nvertigo X helmets. The "revolutionary skydial" broke on each and every single helmet. Talk about a poor design, all it is is a piece of sting. It also does little or nothing to keep the helmet on your head. I also purchased several Oxygen helmets and one came off in freefall also !!!!! I would be very careful if considering a Sky Systems helmet, they seem to have inherant faults.