1,Function: This basalt massage stone relieves pain caused by sprains and strains, relieves stress and muscle tension, soreness and stiffness. Also the stone is ideal for athletes, home care and spas. 2,Quick Heating: This massage stone heats up without water, and can heating in less than 10 minutes, so you can spend just a little time each day relaxing muscles and massaging various parts of body. 3,20PCS: Each pack of 20 different size stones, can be used in any way you like. Easy to replace broken or old stones in the process of use. 4,Convenience: You put inside the case, these stones do not take up much space when not in use. This massage stones are also easy to use, you just need to plug in and heat up. 5,Material: This hot stone massage set is made of glazed round black basalt with a high silica and iron content. And heat preservation time can keep 25 to 35 minutes, which is longer than the other stones. Item Type: 20 PCS Stones Massage Set Material: Basalt, Logs Quantity of Products: 4 x Massage Stones (Approx. 8 x 8cm or 3.1 x 3.1in), 4 x Massage Stones (Approx. 8 x 6cm or 3.1 x 2.4in), 8 x Massage Stone (Approx. 3 x 4cm or 1.2 x 1.6in), 4 x Massage Stones (Approx. 6 x 5cm or 2.4 x 2in) Features: not waxing, not oiling, original ecology Suitable: 1. People of long term facing computer, TV, often play mahjong, often drive cars 2. People of shoulder, neck and back easier get pain, mental tension and stressful 3. People of long term insomnia, neurasthenia, headaches, dizziness, hair loss, memory loss 4. People of insufficient blood supply to the brain, lack of oxygen, shoulder and neck strain, hyperplasia 5. People of long term constipation, belly drainage, gastrointestinal discomfort 6. People of blood disorders, menstrual disorders, dysmenorrhea, etc. 4 x Massage Stones (8 x 8cm) 4 x Massage Stones (8 x 6cm) 8 x Massage Stones (3 x 4cm) 4 x Massage Stones (6 x 5cm) 1 x Bamboo Box