Herbal Concepts largest Comfort Pac. The Herbal Comfort Back Pac provides 100% all natural aromatherapy. The pac is filled with 12 healing herbs and the highest quality, natural grains available. The detailed stitching keeps the herbs evenly distributed, allowing the natural herbal content to contour the curves of your body and help relieve stress, tension, cramps and muscle discomfort. Microwave for instant hot therapy/chill for instant cold therapy. To clean, wipe with damp cloth. Do not submerge herb pac. To store, keep in dry cool place in a resealable plastic bag to increase longevity.