NJB1-YW Floatless Relay is applicable for water level automatic control in industrial facilities & equipments, civil water tower, high cistern, underground conservation pool, etc. The control of automaitic water supply or drainage may be achieved by a simgle operation of the function switch without modifying the user’s connectiong conditons. This product is not applicable for water level control of flammable and explosive liquid, such as oil, chemical liquid, etc.