I like this type of deflator. . I had expensive fakes and now these cheap ones. They work fine once you put them in. It takes trial and error, but once set up, they keep up the same pressure every time. They are permanent. If you are a person who uses a large range of pressure depending on the surface, speed, etc., this type of deflator is not for you. If you want to lose 12 pounds every time you go off the road, these are great for you, with a few exceptions.