Natural Grain Herbal Concepts Body Therapy Reusable Microwave Activated Heat Hot and Cold Packs Wrap For Limb Joint Exterior fabric: corduroy. For limb joint. Exterior fabric: corduroy. 100% natural grain. Filling material: wheat, flax seed, grape seed, cherry pit, lavender, red bean. The adjustable strap will make the pack stay in place when you walk, sit, or stand. The natural grain contour your body and help to relieve stress, tension, cramps and muscle discomfort. This product has been processed by irradiation sterilization.