Once users hop aboard the Waist Twister non-slip surface, they might forget they're burning calories and tightening your core. That's because the massage beads and magnetic-therapy points lining the unobtrusive, portable disc soothe feet and help provide reflexology benefits, which may include improved circulation and alleviated lower-back pain. Features and Benefits Simple twisting motion helps trim waistlines and strengthen abs. Massage beads and magnets may improve circulation and ease lower-back pain Non-slip suface Lightweight, portable design ideal for bringing to the gym, office or a dance marathon. Gender: unisex. Age Group: adult.