Summary This is a mouthpiece for a Fallout Jet prop. To get the container, find an old CO2 cartridge from an airsoft or paintball gun. You can also print the bottle at http://www.thingiverse.com/thing:2010129. Most containers should fit, but just in case, the size of the end of mine was 9.10 millimeters. I designed it using Tinkercad and hope you like it! Check out some of my other designs such as a Lego compatible Halo MA5C Assault Rifle. Even more are on the way soon, possibly including the Halo BR55 Battle Rifle, M6C Magnum, and the ARC-920 Railgun!