if you've ever played paintball you would know exactly what those are. the low end markers use those. they are 12gram Co2 Cartrages.. they pinhole at the top allowing the compressed Co2 out. unless you want to inject Co2 into your engine for a cooling effect your really not going to gain from this.. you can fit more air in your lungs than you can fit in there!

btw.. local paintball store sells those cartrages for $0.25 a peice!

not trying to be a jerk or anything.. just hope you save your cash..