Originally Posted by simm
Here is a pic of one. You can fill it off your existing tank.
Spare Airs are good for one thing...
You know how they say just before you die, you see your whole life flash before your eyes? Well the Spare Air will allow you to get past the teenage years before you die.
I use a 30 on any dive over +/- 80 feet. Call me paranoid, but I would rather have an independent air source that can get me to the surface AND a safety stop, rather than a couple puffs at 3atm.