My hairdresser uses a Chi and thats what I bought. I can't tell you how wonderful this straightener is. I wouldn't have anything else. It was pricey - got it off of Ebay - but it is worth every penny. I know they make various sizes, but I have the standard 1" Chi. If you buy it, you will not regret it. Its a work horse. My hair is thick and wavy and has been difficult to manage my entire life. This works like a dream. No one would guess that my hair is naturally wavy.