Gray beauty roller made with terahertz material, perfect for tightening skin. Smooth massage with blood circulation benefits. Convenient with large and small rollers. - Model Name: Terahertz Roller - Color: Gray - Material: Contains metal parts - Size: Approximately 14cm long Terahertz ore is said to emit electromagnetic waves called "terahertz waves." Terahertz waves have the characteristics of both radio waves and light, and are said to vibrate 1 trillion times per second. Stored at home. Unopened, still in the plastic. If you are a perfectionist, please consider this after understanding, as it may cause problems. Thank you for viewing.