Oh just one more thing, my transformer has a switch on it so you can use it at 12v, 9v, 6v, 4.5v and 3v, the fan is a 12volt but works fine on 12v,9v, or 6v. it will be slower the less power but it works. If you had a volt or 2 over what it needs then it will just spin faster and have a slighlty shorter life span.