I see you are from Oregon... are you by any chance a logger... if you are you no doubt are in great cardio-vascular shape and don't need no stinking spare air...Originally posted by Phil
It appears to be just an extra bit of insurance against running out of air. or malfunctioning equipment.
Course even if you sit behind a desk all day and smoke cigarettes you still don't need no stinking spare air...
Spare air is not insurance ~ it is an illusion of safety...
Spare air is like having house insurance and then suffering total loss by flood and finding out the policy doesn't cover flood damage...
Spare air is like having medical insurance and then contracting Ebola...
Spare air is like having car insurance and driving off a 100 foot cliff but thinking that your insurance will save you...
Spare air is not insurance it is an illusion of safety and that IMO makes it dangerous...