Four-digit LED digital display, capable of long-term monitoring and controlling the pH value and oxidation-reduction value in water. 
Operates on AC voltage, with options for 110V~240V. 
Available in two functional variants: testing only, and testing with control. 

This product enables continuous monitoring of pH levels in aquariums and similar environments. When the pH value exceeds or falls below the set threshold, it automatically activates the power supply to other equipment, such as engaging a CO2 solenoid valve to initiate carbon dioxide supply.