My DD has thick, curly hair and I have thin, wavy hair and any flat iron will work. The trick is, if you want your hair extremely smooth and pin-straight, you HAVE to blow it out first. I learned that at the salon. When you get your hair flat ironed there, they will ALWAYS blow it out first. I use a big, round boars bristle brush for me and DD. I usually part my hair in 4 sections, since dd's is thicker I do hers in about 8 sections. I dry each section with the brush 1st and then follow it with a 1" flat iron. I also use tresemme thermal protection straightening gel and it keeps the hair really nice for at least 2 days.