Filled with flax seeds, this 100% natural accessory also helps relieve neck pain, lower back pain, stiff neck, headaches, menstrual pain, or stomach aches. OPTION 1: Place the cushion in the microwave for about one minute. Turn and knead the cushion to distribute the heat. OPTION 2: Place the cushion on a radiator until the desired temperature is reached. Be sure to check the temperature of the cushion before use! Cold use: The cold hot water bottle is recommended to relieve headaches, cramps, sports injuries, inflammations, and minor bruises. Place the cushion in the freezer for at least 30 minutes or several hours in the refrigerator, ideally in a freezer bag to prevent moisture absorption. Clean and rinse the surface with a damp, soapy sponge, and reheat for 1 to 2 minutes to remove moisture. Dimensions: 13 × 45 × 3 cm.