spark plugs work really great at breaking windows, I always have spares. A socket substitutes for a roll of quarters, and a wrench works good too. I have most of these in my backpack at all times just in case of a break down. They aren't suspicious, and should you ever need to defend yourself they all work good in a bind. But because I live in NH I never have anything to worry about. If I ever felt in any real danger, I'd just carry my glock.