"A thermal brush has bristles, resembling a brush, and a hair straightener does not have any bristles," says New York City-based hairstylist Devin Toth. "For example, a flat thermal brush will give you straight hair, a thermal brush with a tiny barrel shape will give you curl, and a thermal brush with a large barrel shape will give you more of a bouncy blowout." For our review of the best hair-straightening brushes, we enlisted the help of multiple editors, writers, contributors, and hair stylists—who have different types of hair, concerns, desired outcomes.