The CO2-2 has two timers that are used to add just the right amount of CO2 without the wasteful "overshoot" that other controllers have.One timer controls the length of time the co2 is released and the other controls how often co2 is released.C.A.P. strongly believes that the only way to design and manufacture controllers is the right way. That means understanding what expectations customers have, and manufacturing controllers that meet or exceed their expectations. It means paying attention to details and not cutting corners; constantly striving to produce the most innovative products in the industry, using only the finest quality components to ensure many years of trouble-free operation.CAP WARRANTY CAP controls are warranted to be either rebuilt or replaced at the manufacturer's determination for a period of 3 years of normal use. Modification, misuse or abuse voids this warranty.