I have had 3 close friends killed in sprints. All with their Hans on. And none killed with out. I I know one died as a result of this life saving wonder (Sarcasm) and I think it contributed to one other. If you use one you have to have a sternum strap other wise you body will crumple and con form to the shoulder straps thru loss of actual on the body tightness. I know we really don't like them at all. They also restrict rotation helmet movement enough you can see around you well enough causing more incidents. May be OK at big tracks but a quality collar is better in the bull rings.