Meet the Core-Tex Sit Stability Core Trainer: a fitness tool designed to improve your sitting posture. Simply put it on your favorite chair to add instability and strengthen your abdominal muscles and lower back. Core-Tex Sit takes stress off your lower back. By adding motion, you get a dynamic sitting experience.
The Core-Tex Sit weighs only 3.5lbs. It measures 14″ in diameter and 3″ high. You can find out more about it here.