General Application - Heatable, deep tissue massage ball provides effective pain relief anytimeRelief for pain/tightness in neck, shoulders, back, leg, hips and feetMedical Application - Uses 100% natural acupressure and heat to release tight muscles and joints for larger muscles in your lower & mid back, legs, quads, hamstrings, IT band, and calvesDesign Features 7 years of research and testing Diameter 6.5 x 2.5" Microwave for one minute to receive 60 minutes of soothing heat