THERA PEARL products are a modern version of the old school hack of using a bag of peas. The THERA°PEARL back wrap is a great reusable product that helps alleviate back pain. It can be used as a heat pack (warmed in a microwave) or as a cold pack (chilled in a refrigerator/freezer). It is very versatile, can be used on any portion of the back, torso, or even the thigh area. THERA°PEARL back wrap has a doctor recommended use time of 20 minutes per application and to wait 20 minutes in between applications. For those who suffer chronic back pain, are avidly working out, constantly physically active, or for someone who has an injury or pulled muscle this is a great product for you!