This is a small rocket, powered by a 12-gram co2 cartridge. There is a slot to put a small baring in the top to change the center of mass, so it flys straighter. It fits into PVC piping(I think one inch, but don't' hold me to it) and is punctured by a nail. I'll post a nail holder for it soon. This is my first post to Thingiverse(and I'm only in 8'th grade) so don't judge me:)