Eheim CO2 solenoid valve 230V as night shut-off for a CO2 system. About a tim switch, the solenoid valve stop the CO2 supply into the aqaurium.Eheim CO2 Magnetic Valve 230V+ CO2 night shut-off system+ for use with an Eheim CO2 system+ also for use with a CO2 system from other brands+ power connection: 230V/50 Hz+ maintenance-free+ quiet when in operation+ for hose size: 4/6 mm+ power consumption: 1.6 W+ including an non-return valve+ tip: connect the magnetic valve to the aquarium light timer