For Men and Women: It looks like the Flexi, but works a bit differently! The Flexi has a velcro strap closure. Both work fantastically, but some find one closure easier than the other! A reminder brace - Perfect for improved posture, core activation and clavicle support. Relieves stress, tension, stiff shoulders and upper back pain for both men and women. The Classic differentiates from the Flexi because it has an adjustable buckle strap in the back. Why Posture Classic? IMPROVE YOUR POSTURE – Wear with a loose fit as it only tightens when you slouch, encouraging you to straighten up. Body posture affects body language, mood and results. Good posture increases your well being and decreases stress levels while you strengthen back and core muscles. SLIM POSTURE CORRECTOR – Classic is comfortable, adjustable and thin so you can wear it under your clothes. EASY TO USE – Has a velcro strap that makes it easy to put on, take off and adjust while wearing. Wear it during gym sessions, at the office or while traveling.