The best type of posture corrector is one that's comfortable and effective. A soft, nonrigid corrector is a great starting point. Next, consider the area that needs treatment. Depending on your needs, choose from one that covers your neck, lower back, or entire upper body. You want a corrector that provides ease of use. Basically, one that you can wear on or under your clothes. The straps should be adjustable, so you have a comfortable, custom fit.