Thanks Graham I was just going by personal experience really and what I'd watched in F1. You work track side I know.

I saw a colleague of mine suffering after using a CO2 one and it was not good, he was very lucky there were others around.

2009 4/4 Henrietta
1999 Indigo Blue +8
2009 4/4 Sport Green prev
1993 Connaught Green +8 prev