How does it work? The patch contains natural levo menthol, which reinforces the analgesic feeling of coldness, helping to relax tense muscles in the head and neck. For instant cooling, calming relief, use with or without oral medication, whenever headache or migraine pain strike. The patch contains a high percentage of water which works with the bodies natural cooling system helping to cool the body. As the temperature rises the heat of the skin causes the evaporation of water contained within cooling gel sheet which creates a cooling sensation on the surface of the skin. The excellent heat transfer ability is made possible by the gels unique structure which disperses heat freely and maintains a constant and steady cooling effect that lasts up to 8 hours. The size¡¨ºo5*12cm Packing: 1pcs/aluminum foil bag; 4 aluminum foil bags /middle box, 200 middle box/carton.