If you are operating in tropical conditions, two or three should do it. If you operate in extreme cold, same applies. If you operate in extreme heat, same applies. If you operate in mountains, same applies. If you operate in deserts, same applies.
Now did you you have a valid point to make, or are you just being intentionally silly?
(Oops- sorry gaunty, wasn't aimed at you, intended for the slighty obtuse deadleg)
[edited to remove possible offence]
[This message has been edited by Raw Data (edited 03 April 2001).]