I paid $260 for the regulator but unfortunately, family issues came up and now I am selling it. I have only used it for a month and it worked wonderfully in my 29 gallon planted tank. The regulator is designed so that you do not need a bubble counter, the little black box controls this perfectly. Please pm me if it interests you, asking price is $220 for it.
CarbonDoser bubble electronic timer
Medical grade check valve
Perma-Seal (co2 cylinder to regulator seal)