This is a screenshot from a video tutorial on making your own prosthetic parts from 2-liter soda ... see the clear plastic soda bottle which fits over the form after the bottom was removed.

The main portion of the build is made out of plastic soda bottles (2 liter size) to end up with ... After gluing a cone (the blue thing) to the bottom of the bottle, it receives the parachute ...

StratoLauncher IV Ultimate will propel a 2 liter plastic (PET) soda pop bottle over 350 ft. in the sky. Watch the last minute of the assembly video for launch procedure. Supports most .5L ...