... this products is reusable,no times limits. while using it,no need of power. 3,certificate:CE/SGS/MSDS ... freezer), don't need to click the metal disc; take it out after 20-30 minutes for cold use.Warnings : ... heat pads or hand warmers begin to crystallize as it cools, the typically means that there were still some ... and the boiling time will need to be increased. It is best to boil until the liquid is clear ...