HAHA!
I must have sat for about 30 seconds trying to figure out what the stuff we breath was, talk about a brain fart! The best I could come up with at the time was oxygen, but of course it is just air!

Thanks for the other replies, i've had a good search round at the various options mentioned so far.
I'm based in Hemel Hempstead, are there any shops in the surrounding area which have a good selection of match pistols?

thanks