Silent solenoid valve for controlled CO2 supply.Complement to CO2 kits or CO2/pH controllers: solenoid valve for dosing CO2 supply in aquariums. Easy to use: Insert the solenoid valve into the CO2 transport hose of the fertilization system or mount it directly on the JBL CO2 regulator. Targeted CO2 supply: Adjustment of CO2 supply via timer or CO2/pH controller (timer and controller not included). Safe and economical: 12V safety transformer, low heat generation (power consumption: 0.8 W), saves up to 50 e CO2, universal electronic power supply unit. Contents: 1 silent solenoid valve with hose clamping nuts and universal power pack