SISSEL Hydrotemp packs release deep-penetrating moist heat. Moist heat is more intensive and more effective than ordinary dry heat as provided by warming bottles, electrical hot pads or most seed packs. Underneath a pleasant, skin friendly cover special microbeads store pure moisture and release it when microwaved. The effect can be felt and seen. The fine-grained, latex-free filler of the SISSEL® Hydrotemp® adapts to the body’s contours.