(1)Imported 24V noiseless DC motor , less noise and stable . (2)Handpiece tube and PU water-proof tube is durable, not easy to turn ageing and hard. (3)Chair cushion with PU leather, easy to clean and care. (4)Hexagonal membrane, long term use. (5)Solenoid valve is reliable and faultless. (6)High pressure Spring, long term use and faultless.