Hot & Cold pack contains a water based gel which is non-toxic and environment friendly. Gel technology makes the pack flexible even when frozen and helps retain heat and cold for longer. The pack is reusable and is simple and easy to use. To heat the pack microwave for 60 seconds or immerse in boiling water, freeze to chill. Cold therapy can be used for headache, fever, toothache, sprain, bruises, bumps and other sports injuries while heat therapy can be used for muscle pain, spasms, sprain, strain, stiffness etc. Perfect for any body part: Knee, Arm, Thigh, Leg, Foot, Lumbar, Cervical, Upper and Lower Back, Shoulder, Rotator Cuff, Neck, Calves, Shins, Hips and more. Keep one handy in your fridge for a first aid icing emergency or your everyday comfort from pain. Directions of use: To heat the pack microwave for 60 seconds or immerse in boiling water, freeze to chill. Heat or cool the pack as per requirement, place the pack inside the washable wrap included in the box and simply strap on the affected area for soothing relief. The wrap helps in maintaining the temperature of the pack for longer.