Features: Massage Stones: the massage stone is made of lava stones. The basalt stone has great heat retention, perfect for spa and massage therapy. Ergonomic Shape: The flat surface makes the massage stone close to your skin, deeply relaxes your face, provides effective massage, and warms your muscles, improving blood circulation. Application: These massage stones can be used for spa massage and therapy, and also at home. It is suitable for people who often 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: Basalt stone 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 the stone). Frozen method: 1. Wrap in plastic wrap and put in the freezer (this method is recommended) 2. Soak in cold water for more than 5 minutes. Includes: 2 x Massage Stone