The powerful Hot & Cold Percussion Massager provides effective and relaxing muscle relief, loosening tension and preventing soreness. With the 6 interchangeable heads, you can enhance blood circulation by applying the adjustable level of pressure that is just right for you. Use the hot head attachment to release tension and pain in your muscles. Use the cold head attachment to treat muscle inflammation. For best results, place the cold head attachment in freezer for 2 hours. Product Specifications: WATTAGE: 4.7 W VOLTAGE: 7.4V