Welcome climber. We don't flame for a question like this- not even bother to lightly toast. smile

The others have answered the question, but I'll chip in an analogy. BOB is the land-based version of an ejector seat or a life raft. You really hope you never need to use your survival machine, but if you ever need it, you'll be really, really glad you have it.

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-IronRaven

When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.