Back Wrap Hot Cold Maternity Posture Support * The Smart Rail is also Style:Pair (Left & Right) * The Smart Rail is also easily installed between your mattress and box spring and secured tightly with a safety strap * Weight capacity: 400 Lbs * 5 W with a 27 elastic strap attached (unstretched) The original moist heat pack designed for use in soothing sore muscles aches and pains * Designed specifically for relief of nagging lower back pain stomach cramps and leg arm or shoulder aches and pains * Adjustable strap can be comfortably secured in various positions on the body for complete mobility * Use it hot or cold * Filled with 100% natural organic grains * 20