Single Gauge CO2 Regulator+soleniod+bubble Counter
 
CO2 aquarium Pressure reduced regulator with electronic solenoid valve,
precision needle valve will allow you to tune an exact CO2 bubble output
to give you the best and most accurate results. 
The bubble counter has the non-return function. 
New design washer, no wrench needed.
KINDLY NOTE THAT COLOR MAY VARRY FROM PHOTO !!!