NJYW1 Series Floatless Relay is used in control circuit @ A.C. 50Hz60Hz, up to 380V rated supply voltage for liquid level automatic control at places of civil water tower, high cistern, and underground conservation pool, etc. It is capable to realize automatic water supply control or water drainage control according to wiring requirement of user. This product is not applicable for level control for liquidwith poor conductivity such as oil, pure water, flammable & explosive chemical liquid and high density sewage, etc.