This simple hot-pak by Warmies gets the job done when you are wanting soothing heat for relaxing sore muscles. Or, you can freeze it for cold therapy on a hot day. Each one is filled with microwavable flax to keep the heat, and these have a subtle and relaxing fragrance blend. Simply microwave for 60 seconds and it stays warm for up to 45 minutes. Or, put it in the freezer for 30 minutes, and it will cool and soothe. Made by Warmies, a division of Intelex Group. This measures about 18 inches by 5 inches. For cleaning, simply spot clean the outside with a damp sponge, but never submerge in water or wash in the machine.