Cold: Used for bruises, sprains, trauma, hyperthermia and in all situations where cryotherapy is required. Place the pouch in the freezer for at least 2 hours. Use the bag inside the included protection. Heat: Used for low back pain, torticollis, rheumatism, hypothermia and in all situations where heat therapy is needed. Place the bag in a water bath for 5 minutes in boiling water, or heat the bag in the microwave to 650W for a maximum of 1 minute. Use the bag inside the included protection.