1. The machine can obtain accurate reading when the root-canal is moist, but without sodium hypochlorite, hydrogen peroxide, saliva, blood or pulp. 2. Equipped with voice control alarm facility for caution at any time. More convenient for the consumers. 3. Equipped with high-energy 9V battery, which can be used for ten years, cutting the cost. 4. The accessories of the instrument can not be autoclavable under high pressure to avoid cross infection between the patients.