The 66fit R&R Soft Cold/Hot pack features a non-toxic gel that retains heat or coolness for a minimum of 60 minutes. The Cold/Hot pack\'s gel remains soft and flexible after freezing, even in temperatures as low as -20 degrees celsius. Features: Size: 28.5cm x 11.5cm Cold Therapy: Place in freezer for at least 10 minutes before use.  Hot Therapy: Place pack in hot water for 10 minutes, or place in microwave oven (800w) and heat for 30 seconds on a LOW power setting.