... the surface, then we can wear the ice band on the neck ,head and waist etc.3.It will come back ... again.5. Refrigeration materials——Hydrogel does the accumulation of cold,so it will work better if we put it into ... very mind and comfortable ,never too cold because we have sloved the over cold feeling problems of the traditional Phase change ... the detail-pictures below .NO.8 Detail Pictures: Cool Head Band