Features: Massage Stones: the massage stone is made of lava stones. The basalt stone have great heat retention, perfect for spa and massage therapy. Ergonomic Shape: The flat surface makes the massage stone close to your skin, deep relax your face, effective massage and warm you muscle, improving blood circulation. Application: these massage stones can be used for Spa massage and therapy, also you can use it at home. It is suitable for the people who are often to use computers and mobile phones. Note: In addition to being heated, it can be used after refrigerating. It relieves skin irritation and calms and soothes. Specification: Material: Meteorite Size: 55*38mm Usage: Heating method: 1. Soak in hot water for about 1-3 minutes, and keep warm for about half an hour (recommended) 2. Microwave oven heating (May damage). Frozen method: 1. Wrap it in plastic wrap and put it in the freezer (this method is recommended) 2. Soak in cold water for more than 5 minutes. includes:2 x Massage Stone