Hair straighteners are versatile tools that you can use to remove any resemblance of a curl, regardless of your hair type. They work by flattening the follicle of the hair. You can also use your flat iron hair straightener to create bold waves in your hair, even though a hair straightener is not specifically designed to do so.
There are many things to consider when shopping for a straightener, including your hair texture and the size, optional features, and plate type of the iron.
Whether you have baby-fine hair that is soft and flowing or very thick and curly hair that displays frizz at the first signs of humidity, you can find a flat iron hair straightener to match your hair's texture. Hair that is fine and thin is also easy to break and burn. For this reason, look for a quality brand with ceramic or tourmaline plates if you have this type of hair. You should also be sure to look for one that has adjustable temperature controls. Low settings prevent fine hair from burning. 
You should consider buying the best iron you can afford. A quality iron, though expensive, will last a lifetime.  Once you have put all these factors into consideration, finding the best flat iron hair straightener becomes less daunting.