At $230, the Bio Ionic is pricier than any of our top picks. But you get what you pay for. You can truly do with your hair whatever you desire — straight or curled — in one pass. And, if you’re worried about it breaking a few years after purchase, the Bio Ionic comes with a five-year warranty. By investing in a better-quality tool up front, you won’t have to replace your flat iron every couple of years. Plus, the Bio Ionic goes on sale every now and then, so it’s worth keeping your eye out for deals.
Unlike the Bio Ionic’s handy digital temperature control, the Chi Air uses a small dial on the side of the tool that’s harder to read. The dial’s placement makes it not only more difficult to get an accurate reading, but also more prone to being hit by your hand and switching to a new temperature. That being said, most of our testers didn’t mind this minor inconvenience since they don’t expect to change the tool’s temperature often.
The plates in this techy tool house an internal microchip that constantly measures and maintains an even temperature. With no random hot or cold spots, you'll get smoother, straighter, strands in fewer passes. (Spoiler alert: Fewer passes equal less damage). Adjustable temperature settings — from 260 to 410 degrees — make this ideal for any and every hair texture.