UHZ-58/S-UK series plug-in magnetic liquid level controller outputs switch signals for liquid level. The product, when paired with corresponding circuits, can be used for liquid level control and alarm in various open or closed containers such as petroleum, chemical, textile, printing and dyeing, environmental protection, and civil construction. The structural principle utilizes a magnetic float to rise or fall with the liquid level, causing the reed switch at the set position inside the sensor detection tube to actuate and emit a contact on/off conversion signal.