I think they are a bloody goid idea, at worst to have an extinguisher in the car. was driving along m25 with the mrs the other day and saw a 02 reg high end Mercedes whole engine bay on fire.it was horrific, imagine a poor starlet being in that situation.....would bring a tear to ones eye. for the sake of 20 quid I have bought one just because I saw that, could potentially save ure vehicle