The UGEARS Pneumatic Engine may be small, but is definitely mighty, giving a sneak peak inside a functioning steam engine. The model Pneumatic Engine comes to life by either having the user blow into a special socket, or by using an ordinary air balloon. All the parts move as if they were inside a real steam engine, the amazing thing is ? it?s built entirely out of plywood! The Pneumatic Engine comes with its own, built in air pressure tachometer, and two small compartments for storing ?spare parts?.