Thanks WeLuv but I'd seen that post already and the info is out of date... Not looking to sell; just personal use!
Its best left alone, I've took it a few times, but a boy ended up in a coma and died last year through inhaling it. Not worth the risk for a 30 second high.
It is Laughing Gas http://en.wikipedia.org/wiki/Nitrous_oxide The use whipping cream cartridges,
Now for a bonus point Why is it used for whipping cream ?
Tim