Fortuna Hot / Cold Pack Microwaveable-Reusable. Comes in 3 Sizes:

Contains Positioning Pouch Reduces & soothes;

Swelling
Backache
Fever
Headache
Toothache
Menstrual cramps

Prepare the gel pack for warm therapy by following the heating instructions. Then place the hot gel pack in the pouch and then apply it to the MICROWAVE;
Place the gel pack in a microwave-safe container and cover it completely with water. DO NOT PLACE THE GEL PACK DIRECTLY IN THE MICROWAVE
Heat for 3 minutes at full power (based on 600 watt microwave).
Check the gel pack carefully. If the package is not warm enough, you can microwave it in 30 second intervals until the desired temperature is reached.
Carefully drain the water in the container and remove the gel packaging with a towel.
Test the gel pack first before use. If the appliance is too hot, let it cool down before using it!