Completely assembled, Vacuum engine, Sucks a flame into chamber provide power. Hence the name flame eater. Similar in cycle to a Stirling engine. Remember when you were in school and taught about internal combustion engines? Well a vacuum Engine uses external heat to generate power. Like toys that are hard to explain and amazing to watch? Like precision pieces of equipment that are beautifully engineered? Love science? Want a gift for the person that has everything? If so you will want a Stirling Engine.The engines I offer are fully assembled and not a kit.This version uses a small flame to provide heat the to the "expansion chamber". it is a very durable design that should last a long time. it comes with a few spare parts in case you need them .If you would like to see a video of them operating look at You tube and look DStar Vacuum Engine. I am sure you will want one. All my units I sell are personally tested by me (Dstar engines "Star Power") to make sure they work. A full warranty and phone support is offered if you need any help with your engine.