While you might think that a hair iron is only necessary to straighten curly hair, a hair iron is actually a great tool for styling straight hair. A flat ceramic flat iron can help smooth away flyaways and a add sleek shine to your hair. You can also use a flat iron to shape straight hair, and you can use it near your scalp to add volume to limp hair.
We usually roll our eyes at oil-infused heat tools — but you can actually watch this oil being sucked right out of the refillable cartridge in the handle. When you press the iron closed over your strands, the oil vapor seeps through tiny holes to condition and straighten your hair. And don't worry fine-haired friends: It made our tester's hair silkier, but not like she'd dipped it in an oil vat.