Disclaimer: This is NOT a beginner biuld, you wil need experience, a strong mindset, or both.This engine runs off of compressed air and features 2 cylinders. i originally made it as a boredom project and to my suprise, it actually worksYou will need some extra fasteners to complete this biuld along with my recomendations of sand paper and maybe lubrication of some sort.Extra fasteners:1/4 20 bolts 8 1in long4 2 in long8 1/4 20 threaded nutsNOTE: This Project requires the use of 3 ball bearings, you can either go out and buy a pack, or you can buy a fidget spinner and use the 3 that it will come with. This uses 608 size bearings. you will need some sort of wrench for tightening bolts. Enjoy!